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Weight Management & Obesity

  • The cause and cure for seasonal weight gain

    Many of us experience some degree of weight gain during the winter season. Some might argue that it is because we need to eat more during winter to keep warm (not true), some say it's because we do less outdoor activities in the cold. Myth or truth, this article explored the scientific findings behind the possible cause of seasonal weight gain and the ways to compact it. The information contained in this article is also relevant to people who have mood slumps or carb cravings due to a change of environment or weather. If you fall into any of the above categories, tune in.

    First thing first, yes, in general, some people are indeed more susceptible to weight gain during winter seasons. The cause of seasonal weight gain is mostly due to environmental factors, however, a possible genetic component has also been postulated. We do tend to eat more in winter, and especially crave for carbohydrate-rich foods, not because they can keep us warm, but they somehow can make us feel better. Does this sound like you? Here is why…

    SAD and Co.

    Yes, that's right, winter makes some of us SAD, acronym for Seasonal Affected Disorder, also known as seasonal depression. SAD is said to be "a combination of biologic and mood disturbances with a seasonal pattern", which usually occur in the autumn and winter and ends in spring and summer (Kurlansik and Ibay 2012, American Family Physician). The cause of SAD is largely due to the changes in lengths of days/nights and drop in temperatures in winter compared to summer. It's said that up to 10% of the population in the US has SAD, with a higher incidence in women than men (Miller 2005, Alternative Medicine Review). People with SAD can experience changes in mood, energy and appetite, which can result in depression, fatigue, carbohydrate consumption especially with cravings for sweats and starch-rich food and consequently result in weight gain. A study that analysed the eating habits of female SAD sufferers found that SAD patients are prone to emotional eating, thus leads to a higher chance of seasonal weight gain and a higher BMI compared to non-SAD sufferers (Krauchi 1997, Comprehensive Psychiatry).

    There are a number of possible explanations for the cause of SAD, including genetic predispositions, neurotransmitter abnormalities, both sound quite serious and a bit of gibberish to most people. However, neither really explains the seasonal rhythm of SAD. I'd go and seek professional medical help if your SAD is that serious. On a more relevant note, one of the most obvious differences between summer and winter seasons, other than the change in temperature, is the shortened daylight period, which will consequently affect a person's circadian rhythm (biological clock) (to learn about the circadian rhythm and BMI please read the Dec 2012 issue of Fit Lifestyle magazine). You don't really need to have clinical SAD to experience similar symptoms, and below are what I personally think is relevant to an average Joe like you and me that suffers seasonal mood and weight changes.

    The slight change in circadian rhythm will alter the production of melatonin, an endocrine hormone and a powerful antioxidant produced by the pineal gland into the blood. As the production of melatonin is kick-started by darkness and inhibited by light, it can be affected by the shortened daylight of winter. It was found that there is a delay in melatonin secretion in response to darkness in clinical SAD sufferers, and there is a difference in melatonin secretion pattern/levels in SAD patients as compared to normal people (Miller 2005, Alternative Medicine Review). A trial of 58 SAD patients were given high-dose of slow-release melatonin and a significant improvement in quality of sleep and vitality were observed, however melatonin therapy had no effect on mood (Leppamaki et al, 2003, European Neuropsychopharmacology). Go and see your doctor if you suspect you have melatonin issues.

    One cannot talk about mood changes without mentioning serotonin, a hormone that controls you mood, appetite and sleep. Inadequate levels of serotonin in the brain can cause carbohydrate cravings. Serotonin has also been found to be a controller of body weight by regulating the body's energy balance. Brain serotonin levels are relevant not only to SAD sufferers, but also to anyone who has mood swings associated with environmental or weather changes. For those who feel the cravings for carbs, it may be caused by inadequate serotonin levels in your brain. The best natural ways to increase serotonin levels, according to Young (2007, Journal of Psychiatry and Neuroscience) are:

    • Exposure to bright light. Uh-Huh! We live in a bright light-deprived society, where many people spend best part of their day indoors. The lights commonly used indoors do not have enough lux (luminous flux per unit area, a way to measure light intensity) to make you secrete enough serotonin. Whereas even the outdoor light on a cloudy day could make you happier. Get outdoors as much as possible without getting sun burnt, you could be happier and lighter in the process, kill two birds with one stone as they say.
    • Do exercise. It has been scientifically proven that the exercise can make you happy. It was hypothesized that the decline in vigorous physical exercise, in particular, effort based rewards compared to our ancestors may contribute to high levels of depression in the current society. Adequate exercise can increased serotonin levels and hence decrease carb cravings, and you can stay active and healthy in the process.
    • Diet. There is quite a bit of incorrect information floating around about this one. As serotonin is the metabolic product of tryptophan, ingestion of purified tryptophan has been found to increase brain serotonin levels. However, ingestion of food containing tryptophan does not, as the other amino acids contained in the food will compete with the tryptophan. The popular myth that is eating high protein food such as turkey can increase serotonin level, is false; similarly, the popular believe of eating bananas, which do indeed contain serotonin can improve mood, is also false, as the serotonin contained in bananas does not cross the blood-brain barrier to get into our brains to make us happy. In order for a food to increase brain serotonin levels, the tryptophan content of the food needs to be much higher than that of other amino acids, some example of those foods are specially cultivated chickpeas and alkali-processed corns.

    Vitamin D

    Some have stated that the reduced vitamin D synthesis caused by a reduction of sunlight (UV-B radiation) in winter compared to summer is one possible cause of seasonal weight gain and obesity (Foss 2009, Medical Hypothesis). This seems reasonable and indeed, low vitamin D status has been linked with an increased risk of weight gain and obesity. Vitamin D is thought to play a role in adipocyte (fat cell) death and genesis as well as lipid metabolism (Song and Sergeev 2012, Nutrition Research Reviews). However, taking vitamin D (often along with calcium) doesn't seem to make you thinner, as clinical intervention trials using vitamin D yielded controversial results. There is no concrete scientific evidence in humans to indicate supplementation of vitamin D can prevent obesity in real life situations, yet.

    Some may also argue that vitamin D deficiency is associated with depression and can lead to "emotional eating" and hence weight gain. Well, believe it or not, that is also a myth, well, more like an exaggerated truth. Yes, there is an association between low vitamin D levels and depression however, there is currently insufficient evidence to say that vitamin D deficiency is the antecedent cause or consequence of depression (Parker and Brotchie 2011, Acta Psychiatrica Scandinavica). So can lower vitamin D synthesis in winter cause weight gain? Not sure about that, but in case it does, get into the sun more often and consume food or supplements that contain vitamin D will be sufficient.

    It's not me, blame the genes!

    There seems to be a gene linked to everything these days and weight gain is no exception. There is an established genetic component in weight related disorders such as obesity, where a percentage of people have the genes to allow them to gain weight more easily than others. This phenomenon has puzzled scientists as the survival of these weight gain genes in the human population defies the theory of "survival of fittest", there is nothing "fit" about been obese.

    Two main theories have been postulated in order to explain the presence of fat gaining genes, the "thrifty gene hypothesis" initially proposed by James Neel in 1962, and the "drifty gene hypothesis" first proposed by John Speakman in 2008. Scientists supporting each of the hypothesis argued with each other about the details of what kind of selection pressure required during the history of mankind to allow these genes to survive. Let's leave that part to the scientists, what is relevant, is that, scientists from both sides agreed that there is a genetic predisposition in a population of people so that some people are more prone to weight gain than others. This genetic predisposition is kept there because historically speaking, ancient humans faced famine, seasonal shortage of food and predation (or lack of), hence needed to store fat to have the energy required for survival during periods of abundance. In a developed modern society however, for instance, Australia, there is a perpetual abundance of food, and a lack of predators that feed on us humans. What was historically advantageous for survival became the culprit for causing widespread weight gain and obesity.

    So, some people are genetically prone to gain weight, big deal, because ultimately, weight management is all about calories in and calories out, the choice is yours. If you eat well and exercise adequately, there is really no reason for you to gain weight any more than other people. Think of the number of calories required per day as the speed limit, and to have the "fat gene" means you have a relatively faster car than the average shopping trollies found on roads. It's easier for you to speed if you put your foot down, but there's no excuse, watch the speedometer and exercise discretion, you are more than capable of staying within the limit. It may be is the genes, but it is definitely up to you.

    Final words

    The purpose of this article is to show the scientific understandings behind seasonal weight gain, mood slumps and emotional eating. Not to succumb to the food cravings, instead, continue to eat healthy, spend more time outdoors and do adequate exercise, are probably the most effective natural cures to deal with these kinds of problems. It is all in your hands.

  • Targeted fat loss

    targeted fat loss

    Targeted fat loss, also known as spot reduction, has long been an intense area of focus by infomercials, fitness and supplement companies and sports magazines. The idea of target fat loss where you lose fat more readily in areas you exercise more seems to be reasonable and intuitive. It also appeals to the general public, as most of us tend to gain fat in certain areas while not others, causing the prevalence of "love handles" and "beer bellies" among us. The reality though, it's that the basic physiology of the human body prevents targeted fat loss from happening no matter what form of exercise you do, and this is why: Fat is stored in the human body as triglycerides, they have to be broken down into glycerol and free fatty acids and then enter the blood stream before can be utilized by muscle cells. This means that the fat burnt from whatever you do can come from anywhere in the body, not just the area you've worked on. Scientific studies conducted on athletes have shown that prolonged, intense work-outs targeted at one part of the body does not reduced the amount of subcutaneous fat in the trained area compared to the rest of the body. Fat loss is universal.

    The most effective way of losing fat is through good calorie burning exercises, for instance, high intensity interval training. Sit-ups alone don't burn enough calories, and while they can indeed improving your core strength, they do almost nothing to get rid of the fat on your belly. Fat loss cannot be targeted, if you want to lose weight, do exercise that burn the most calories.

  • Glycemic index, its perks, and limitations

    The glycemic index or GI is the measurement of the blood sugar level increase in response to consuming carbohydrates (usually 50 grams) contained in foods. The value of GI is relative to that of pure glucose, which has a GI of 100. It is acknowledged that a GI of 70 or above is considered as high, a GI of 56 - 69 is medium, and a GI of 55 or less is considered as low. Foods with a higher GI number will induce a greater and more rapid the blood sugar response after ingestion; and conversely, food with a low GI will induce a more slow and steady glucose release.

    The concept of GI was initially introduced by Jenkins et al. in 1981, originally designed as a food guide for people with diabetes. Due to the importance of carbohydrates and sugar in body's metabolism and function, GI has since been widely adapted by the non-diabetic population as a guide to optimize diet and performance. Here we have a brief look at the role of GI control in weight management, exercise and limitations of using GI as a sole measure for blood sugar control.

    Effects of GI on weight management and health

    It is estimated that there are over 1 billion overweight adults in the world and 300 million of those are obese. It has been proposed that the population's increased consumption in high energy, high fat and high sugar diet coupled with low physical activity are the main causes of overweight (Lopes da Silva and de Càssia Gonçalves Alfenas, 2011, Nutrición Hospitalaria). Being the main energy course of human diet, the amount of carbohydrates ingested thus has a significant influence on human health.

    GI links to obesity and other health problems

    There is evidence suggesting that low GI diets may be protective against the development and obesity of related disease such as type 2 diabetes and coronary heart diseases (Barclay et al. 2008, Amercian Journal of Clinical Nutrition). Low GI diets have been linked with improved BMI (Ma et al. 2005, American Journal of Epidemiology). High GI diets have been linked with increased body fat mass, body weight and waist circumference in women over a 6-year period, but not in men (Bare-Bruun at al. 2006, American Journal of Clinical Nutrition). A diet based on high carbohydrates, low GI foods has been found to reduce the sugar and insulin hike post-eating without increasing LDL-cholesterol (the bad cholesterol) or serum triglycerides (level of fat in blood) (Brand-Miller et al. 2009, Journal of the American College of Nutrition). Low GI diets have been found to be more effective in promoting weight loss in children and adolescents than low fat diets (Esfahani et al 2011, IUBMB Life). A meta-analysis concluded that (after analysed 6 trials) strict low GI diets resulted in significant reduction in weight, total fat mass, and BMI compared to people with normal diets (neither high GI nor low GI) in adolescent and adults (Thomas et al. 2007, Cochrane Database of Systematic Reviews). Another meta-analysis study compared results from 23 studies and found that low GI diets can effective induce weight loss (Livesey 2008 et al. 2008, American Journal of Clinical Nutrition).

    There has been inconclusive evidence showing that low GI diets may reduce the risk of various cancers, such as breast cancer, prostate cancer, colon cancer and pancreatic cancer, however, the results of various studies are inconsistent and as such this is an area warrants further scientific investigation (Esfahani et al. 2009, Journal of the American College of Nutrition). Nevertheless, there is overwhelming evidence to show that low GI diets are effective in weight management and can reduce the risk of type 2 diabetes, coronary heart disease and possibly a range of other health related complications such as cancer.

    GI is affected by combining different types of food

    GI provides values for individual foods. However, when a food is included into a meal, the GI of the meal will not be the same as the GI of the individual food. Contents from other co-ingested food, such as protein, fat, soluble dietary fiber and even acidic compounds will have an influence on the glucose and insulin response to the meal as a whole (Bornet 2007, Apetite). It is generally agreed that the GI of a meal should be the calculated by the GI of individual food weighed by their percentage of carbohydrate contribution to the entire meal. Thus the overall GI of a meal can be reduced (without being unhealthy) by incorporating foods contain high levels of dietary fiber.

    GI and exercise

    The manipulation of GI for optimizing exercise performance and post-exercise recovery is an exciting new area of research in sports nutrition. However, studies to date yielded mixed results on whether GI manipulation can actually enhance performance. More research into the effects of GI on exercise is clearly required. Therefore, it is important to look at the findings of these studies in a critical manner. Here we present to you some of the recent findings regarding to GI manipulation and exercise.

    Effects of GI on exercise and recovery

    It has been found that the ingestion of carbohydrate before and during a workout can improve performance. For details of this please refer to the article "Are sports drinks beneficial during workouts?" from the previous issue. While a small number of studies suggested that eating low GI foods before an exercise is beneficial, as the more sustained release of glucose can maintain the energy levels of athletes during the session, the majority of the studies concluded that GI of the ingested meals before exercise has no impact on performance (Donaldson et al. 2010, International Journal of Sports Nutrition and Exercise Metabolism). It is worth noting that a portion of the small number of studies where a pre-exercise low GI meal did enhance performance, the subjects were conducting workouts at lower intensities (3 out of 4 such studies showed improvement). The catch is that this improvement of performance would diminish if the intensity was maxed at any time during the exercise (Mondazzi and Arcelli 2008, Journal of American College of Nutrition). Therefore, to benefit from a low GI pre-exercise meal from a performance point of view, one has to maintain a consistently low intensity performance throughout the entire course of the workout.

    On the other hand, there's good evidence suggesting that consuming pre-exercise low GI foods can prevent hypoglycemia (low blood sugar levels) that are usually experienced towards the end of prolongs exercise, as compared to consuming high GI pre-exercise foods. Preliminary research also showed that consuming low GI foods before exercise can induce greater plasma free fatty acids levels in comparison to consuming high GI foods. Free fatty acids are used as energy fuel and can be oxidized by the muscle during exercise, therefore support better energy metabolism. Even though the performance enhancing property of a low GI pre-exercise meal is highly questionable, there is enough evidence to show that low GI foods can at least enhance energy metabolism and thus can be deemed as more beneficial in comparison to high GI foods as pre-exercise meals.

    Effects of GI on post exercise recovery

    In contrast, it's almost universally agreed that high GI foods/meals can increase muscle glycogen resynthesis, replenish glucose storage after a workout session. It has been shown in one study that the increase in muscle glycogen concentrate from the end of exercise to end of 24 hour recovery period was 50% greater in people consumed high GI foods in comparison to those who had low GI foods (Burke et al. 1993, Journal of Applied Physiology). Consuming high GI foods after a workout can speed up immediate post-exercise recovery.

    The limitations of GI and glycemic load

    Many manufacturers advertise their food as having a "low GI" and this may have created misconceptions in the public that low GI = healthy. Well, here is something for you to think about: a super supreme pizza from a popular fast food franchise has a GI of 36, whereas green peas have a GI of 51; here is another one, the GI of premium full cream vanilla ice cream is 38, and the GI of grapes is 59; and there is one more, the GI of watermelon is 71, whereas the GI of microwave chicken nuggets is 46. In each case, the junk food wins the low GI contest hands down compared to natural fruits and vegies. But would you really honestly think a super supreme pizza is healthier than fresh green peas? Our examples show that lower GI doesn't necessary mean healthier, what is it then?

    GI is originally created as a simple tool to measure of how quickly the blood sugar level would rise after consuming 50 grams of pure carbohydrate equivalent from a specific food. And that is that, it doesn't measure fat content, or calories, or additives, it is only an index to predict sugar levels in blood in response to consuming carbohydrates. This means that food contains pure trans fat (no carbohydrates) would probably have a GI of close to 0, and trans fat is certainly not healthy. On top of that, GI doesn't tell you how much carbohydrate there is in a specific type of food either, and this is the real limitation of using GI as a sole gauge of sugar control. As we stated before, GI is established by measuring the change in blood glucose levels after consuming 50 grams of carbohydrates. Now, carrots and super supreme pizzas have a similar GI, however, it would require a lot of carrots to equate 50 grams of carbs and it is unlikely for anyone to eat that many carrots in one serving. This means the carbs in carrots would have a much-reduced effect on blood sugar in real life situations than the published GI. In contrast, pizzas contain a much higher percentage of carbs and it would not take much to consume the 50-gram portion. You see the problem? It is okay to compare GI of similar types of foods. But comparing GI dissimilar foods without knowing their carbohydrate content can be very misleading, it's like comparing the weight of people without knowing their heights and gender. People in the profession realized this limitation of GI and hence another form of measurement was developed, this is called glycemic load, GL.

    GL combines GI and the amount of carbohydrates contained in a serving of a particular food, gives a much fuller picture on how foods can affect our blood sugar. A GL of less than 10 is considered as low, 11-19 is considered as medium and 20 or more is considered as high. Watermelon has a GI of 71, that is quite high, but as it only contains around 5% carbs, that gives each serving (120g) a GL of 4, which is low. In contrast, even though s super supreme pizza has a much lower GI compared to the watermelon, each serving (100g, just under 2 slices) would yield a much higher GL of 9, that's not too bad actually, considering how unhealthy we think fast food pizzas are.

    This brings me to the final point that I want to make: both GI and GL are measurements of the effects of carbohydrate on blood sugar ONLY, and they can only measure foods that contain carbs. Pure fat without any carbs would have a GI and GL of both 0, but it is by no means healthier than fruits and vegies with much higher GI/GL. Two slices of super supreme pizza may have a GI and GL in the relatively lower range, but it also contains quite a bit of fat and is quite high in calories, both are not accounted for in the GI and GL measurements. That being said, GL is a more sensible way of measuring how carbohydrates in a particular food can affect blood sugar levels compares to GI, and should be used in conjunction with other criteria to assess the quality of a particular food.

    The infamous last words
    The GI/GL are nifty tools to predict blood sugar response after ingesting food. They can be used to optimize diet in order to achieve a better health. Use it wisely, don't abuse it.

  • Biological clocks, circadian rhythm and weight control

    Many associate weight gain with eating high fat, high calorie food, and a lack of exercise. Recent advances in medicine discovered that there is another important factor, possibly more important than the type of food you eat, which could affect the body's weight. That is our own biological clock. Most of us know that the "biological clock" is important in regulating the daily functions of our bodies, what we don't realize, is just how important this clock really is; and the fact that the "biological clock" is actually an intricate network of "clocks", which are made up by a group of molecules that is present in nearly all cells throughout our bodies. This means almost every single cell in our body has its own clock. All these clocks are controlled, synchronised and coordinated by a master clock in the hypothalamus of the brain called suprachiasmatic nucleus pacemaker neurons. The biological clock influences almost all physiology and behavior in humans, such as sleep-wake cycles, cardiovascular activities, endocrine system that controls the body's metabolisms and hormone levels, kidney activities, and gastrointestinal and liver functions. In addition, the biological clock has been linked directly to lipid (fat) metabolism (Froy 2010, Endocrine Reviews). The disruption/alteration of these clocks will have implications on the gastrointestinal and metabolic functions of the body and consequently influence our food digestion, processing and absorption that are essential for maintaining a healthy body weight and personal well-being.

    The regulation of our master clock is based on the 24-hour light and dark cycle where our earth rotates along its axis. As such, the principle signal for the regulation of our master clock is light, which then sends output signals to the clocks in other cells of the rest of the body to synchronize their functions. This system allows the body to produce optimal functions at optimal times within a 24-hour day. However, unlike the master clock in the brain, the individual clocks in our tissues can also be affected and reset by stimuli other than light, such as eating times. As a result, this can create time "misalignment" between individual clocks in our body and the mater clock in the brain.

    Circadian rhythm is the daily physiological and behavior patterns driven by our biological clocks. Part of its functions is metabolizing food and nutrients and managing energy input and expenditure, hence maintaining optimal body weight. This rhythm can be disrupted by our own voluntary behaviors, such as irregular eating habits or working irregular shifts, outside the control of the master clock in our brain. When time misalignment occurs between different parts of the body, the balance of the body's energetics and metabolism will be disturbed, and potentially serious health related issues would follow, including obesity and diabetes (Wong et al. 2007, PNAS; Scott et al, 2008, International Journal of Obesity), which in turn will affect circadian rhythm, creating a vicious circle.

    Ok, until now I have emphasized enough about the importance of our biological clocks and circadian rhythm in maintaining a healthy body weight, and probably scared enough people about the potential metabolic and weight management complications associated with the disruption of this rhythm. The reality is, we live in a highly stressful and demanding society, it is almost impossible for an average Joe like you and me, to plan our lives based on our innate rhythms and clocks. We need to work with other people's schedules, we have responsibilities on our shoulders and deadlines to meet, all at the expense of our circadian rhythm. But remember, at the end of the day, we neglected one thing that is the most precious to us, our own health. Although it is unrealistic to plan our daily lives fully based on our own exact circadian rhythms, partly because even with all the advanced medical technologies at hand, we are still not sure what the precise rhythm for each organ is, we could follow some general principles, which would put us more or less on the ball park.

    Evidence has indicated that there is a direct link between the fluctuation of the body temperature of a mammal throughout a day (yes, the body temperature of warm blooded mammals fluctuates) and circadian rhythm (Buhr et al. 2012, Science). By looking at a graph of an average person's body temperature cycle, it is not hard to figure our how we should plan our daily activities. The body temperature is an indication of metabolic rate, and it is at the lowest at around 6am each day and gradually increases as the day goes on. There is a little dip in temperature at around 1pm, which is why many of us feel tired and sleepy at around that time. Body temperature reaches its highest level at around 6pm and then it's all downhill from there, until reaching the lowest point at 6am, the cycle is complete.

    circadian-rhythm

    Since we first came to existence, our body is designed to fast overnight and only eat during the day. This practice follows our natural circadian rhythm and allows our organs and tissues to properly rest and recover from a day's activities. However, we now live a very different lifestyle compared to what we are evolved as humans to live. This disrupts the metabolic pathways controlled by our natural circadian rhythm, and some speculate that it is one of the main causes of the current obesity epidemic in many first world countries.

    It has been shown that eating at night is less satisfying than eating in the morning, which results in over-eating (de Castro, 2004, Journal of Nutrition). Nighttime eating can result in higher fatty acid uptake and triglyceride storage in scientific studies conducted in animals (Bray and Young, 2007, Obesity Review). A more recent study also found that mice eating during a restricted 8-hour period are significantly leaner and healthier than those consumed the same amount of calories but were allowed to eat freely throughout the day, regardless of the content and quality of the diet (Hatori et al. 2012, Cell Metabolism). This suggests that having a high fat diet is not the main culprit for weight gain. The time which people eat their meals can have a bigger impact on body weight and metabolic functions. If the Hatori study is applicable in humans, by consuming food frequently only during the 8 hour day period and fast at night, we will cure obesity, regardless of what type of food we eat. How about that?

    Another important aspect of maintaining correct circadian rhythm is sleep. Sleep depreciation, short sleep and poor sleep quality have been associated with diabetes, higher BMI, metabolic syndrome, increased appetite and obesity (Huang et al. 2011, Journal of Clinical Investigations). People who habitually sleep less than 6 hours or over 9 hours per night have an in crease risk of developing type 2 diabetes and impaired glucose tolerance (Gottlieb et al. 2005, Archives of Internal Medicine). The duration of wakefulness at times when one should be sleeping is directly related to BMI and waist to hip ratio independent of age, sex and physical activity (van Amelscoort et al. 1999, International Journal of Obesity Related Metabolic Disorders). So if you want to be lean, make sure to sleep 7-8 hours a day, can't be that hard!

    It is true that many of the studies mentioned above were conducted using animals not humans. However, the biological clock is present in all living things on earth, even in plants. Its function to regulate the body's physiology and behavior based on the 24-hour earth cycle is shared across species. Therefore, it is reasonable to assume that findings from animal studies can be translated into humans, possibly with small variations of course.

    Even though living a balanced life based on the biological clock and circadian rhythm has been described in alternative medicine for centuries, it is still a relatively new field in modern western medicine and science. Modern technologies however, provided concrete scientific evidence linking the biological clock with the well-being of the body as well as obesity. Thus by adapting eating/sleeping habit with this rhythm, one can maximize the body's potential, and subsequently improves its well-being.

    An adaptation of the appropriate eating/sleeping pattern for obtaining the ultimate lean body based on the circadian rhythm should look something simple like this: eat regularly during the day, have more food in the morning and gradually decrease the amount as the day goes by; try not to eat at night if you can help it and make sure to get 7-8 hours of sleep per night. Sounds simple, right? Of course, each person is different. This is just a basic framework that can be modified based on one's own personal circumstances. The important thing is that you know the science behind it.

    Researching and writing this article made me realize just how in-one we are with our surrounding environments, the earth and even the universe. We function by the basic rules of nature, regardless of how superior we think we are compare to other organisms on earth. We all want to be healthy and feel good about ourselves. We pursue that by taking the best supplements, go through the tedious exercise regimes, eat some of the most ridiculous foods. They do work, however, we forgot the most basic and important factor, the rhythm of ourselves. Play by rule of nature and you will live a healthy and feel-good life.

  • Aspartame

    Aspartame (additive no. 951) is a non-nutritious, low calorie artificial sweetener used in over 6000 food products. It is commonly found in diet sodas, Equal®, sweetened low fat yogurt, sugar free deserts, some condiments, certain sweets and sugar-free gums. The use of aspartame is approved by the US (FDA), European Union (EFSA) and Australia/New Zealand (FSANZ) food safety authorities and is considered safe for human consumption by over 90 countries in the world (Acceptable daily intake at up to 40mg/kg/day of body weight as of 2006).

    A survey conducted by the Cancer Council of Australia in 2003 found that most Australians consume 6-15% of the established acceptable daily intake of aspartame per day, which was well below the level where adverse health effect could occur. To put this into perspective, Diet Coke contains around 0.52mg/mL of aspartame. This means, a 60kg person would need to drink around 4.6L of Diet Coke per day to reach the upper limit of the acceptable daily intake for aspartame. If you prefer Coke Zero, which contains approximately 0.24mg/mL aspartame, then one 60kg will have to drink 10L of that stuff a day to be considered unsafe. That is quite a lot of liquid and it's very unlikely for anyone to consume that much fluid in a day.

    What was generally agreed on by most food safety governing bodies, is that aspartame, even though can be damaging to human health when consumed in high doses, is safe for normal human consumption as the average aspartame ingested daily per person falls well within the upper limit of its acceptable daily intake quantity. That sounds quite harmless, I mean, too much of anything can be damaging to health, even drinking too much water can cause hypernatremia (water intoxication) and may potentially lead to death, no kidding. So where did all these controversies surrounding aspartame come from?

    Historically, there has always been controversy surrounding the use of aspartame, the head of FDA was fired in 1981, allegedly after refusing to approve the legalization of aspartame (Cancer Council of Western Australia, 2010, accessed on 10th December 2012). Since the legalization of aspartame, there have been a number of reviews by food safety authorities over the safety of its consumption, and each time the reviewing organization maintained the position that aspartame is safe for human consumption.

    The most recent controversy over the safety of aspartame consumption that lead to a new round of reviewing and re-evaluation appeared to sprung from 2 independent studies published in 2010. One study investigated the long-term carcinogenic (cancer causing) effects of aspartame in mice (Soffritti et al. 2010, American Journal of Industrial Nutrition) and concluded that the life-long consumption of aspartame can result in liver and lung cancers in the mice tested. The other study analysed 59,334 Danish pregnant women and made the association between artificially sweetened soft drink intake and the increased risk for preterm delivery (Halldorsson et al. 2010, American Journal of Clinical Nutrition). In response, the EFSA conducted scientific evaluations on the above 2 studies and released its statement on February 2011. In the statement, EFTA pointed out the fatal experimental design flaws of both studies mentioned above, and rightfully concluded that neither provide sufficient evidence to demonstrate that aspartame is carcinogenic or can increase the risk of preterm delivery. Based on available scientific evidence at the time, the EFTA stated that aspartame is safe for human consumption.

    A number of studies regarding to the safety of consuming aspartame has been published since EFTA statement on February 2011. Below are snippets of some of the scientific literatures available since 2011 regarding the safety of aspartame:

    • It was found that the consumption of equal or greater than 1 daily serving of diet soda can slightly increase the risk of non-Hodgkin lymphoma and multiple myeloma in men but not in women compared to those compared to caloric sugar-sweetened soda, the author concluded that the study results indicated the "possibility" of a detrimental effect of aspartame on the risk of cancers tested (Schernhammer et al, 2012, American Journal of Nutrition).
    • A study found that the long-term consumption of aspartame can lead to an imbalance of antioxidants and pro-oxidant status in the brain in rats (Abhilash et al, 2012, Drug and Chemical Toxicology).
    • Chronic exposure of aspartame can result in detectable methanol in blood and subsequently induces oxidative stress in rat brains (Iyyaswamy and Rathinasamy 2012, Journal of Biosciences).
    • A medical case report found that the consumption of aspartame caused systemic allergic dermatitis in a 37 year old woman (Veien and Lomholt 2012, Contact Dermatitis).

    Sound scary isn't it? Well only if the results of the studies are scientifically sound. Perhaps in response to the new studies emerged describing the possible adverse effects of consuming aspartame, on May 2011, EFTA was asked by the European Commission to conduct a full re-evaluation on the safety of aspartame. On June 2011, EFTA launched a public call for scientific data on aspartame and the re-evaluation is expected to be completed on May 2013.

    Many consume artificially sweetened food and drinks as part of their weight management regime. The intake of aspartame in place of caloric sugar does not cause weight loss if a person consumes the same amount of calories. Interestingly, it has been found that consuming aspartame without knowing can lead to reduced total calorie intake whereas knowingly ingesting aspartame can increase overall energy intake (Yang 2010, Yale Journal of Biology and Medicine). So if you want to lose weight, either ingest aspartame in place of caloric sugar without knowing it, or just simply eat healthy and restrict your overall daily energy intake. The long-term effect of artificial sweeteners on children and adolescents is unknown and its potential role in weight management in relatively unclear (Foreyt et al. 2012, The Journal of Nutrition). Additionally the American Heart Foundation and American Diabetes Foundation also issued a statement stating that there are insufficient data indicating that the use of artificial sweeteners in place of caloric sweeteners "reduced added sugars or carbohydrate intakes, or benefit appetite, energy balance, body weight, or cardiometabolic risk factors" (Gardner et al. 2012, Circulation). Thus, I suggest you to exercise caution when using artificial sweeteners such as aspartame as part of your weight management regime, until more concrete scientific data on the safety and efficacy of these sweeteners are available.

    So what's my position on aspartame? Well, I myself am guilty of consuming decent quantities of diet soda each week. After researching for this article, the can of diet soda that usually sits on the side of my computer when I'm having the writer's block was replaced by a glass of spring water. I am eager to see the final results of the EFTA re-evaluation and their soon-to-be updated recommendations regarding to aspartame consumption. Until then, I will be on an aspartame elimination diet.

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