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Weight Management & Obesity

  • Calories are not created equal

    The balance of our body weight can be seen as an act of balancing energy input and energy expenditure. There are four subcomponents that contribute to energy expenditure: resting energy expenditure (the energy used to just stay alive), thermic effect of food (the energy needed to digest food), activity energy expenditure (energy used from doing activities) and total energy expenditure (the combination of the 3 above). Calories-in-calories out is the traditional model for weight gain and weight loss. Many professionals hold the belief that a calorie is a calorie, no matter what you eat. However, it has became more apparent that not all calories are created equal, some calories will make you burn more energy, through altering one or more of the 4 subcomponents of energy expenditure.

     

    A study conducted by Ebbling et al and published in the prestigious The Journal of the American Medical Association in 2012 compared the effects of three common diets, low-fat diet, low-GI diet and low-carb diet on energy expenditure. In contrast to the conventional recommendations, the study showed that the low-fat diet tested was probably the worst diet for weight loss and maintenance compared to the low GI and low carb diets. The authors concluded that low fat diet "produces changes in energy expenditure and serum leptin that would predict weight regain".

     

    In agreement with some available diet programs, the study showed that low-carb diet resulted in the highest resting energy expenditure and total energy expenditure in most test subjects compared to the low-fat and low-GI diets. Test subjects on a low-carb diet used on average 67kcal per day more resting energy than subjects on a low-fat diet and 29kcal per day more compared to those on a low-GI diet. The figures shown represented average data from all test subjects, there were of course exceptions, some people tested seemed to respond better and burn more energy on low-GI and low-fat diets. One has to choose what is more suitable for them based on their own experiences.

     

    Although low-carb diet is the most beneficial in terms of energy expenditure and a number of metabolic syndrome components, prolonged enforcement of this diet can increase the secretion of the stress hormone cortisol in the body. High cortisol levels may in turn promote fat gain, insulin resistance and cardiovascular diseases. Therefor, low-carb diet may not be a long-term solution to weight loss and maintenance.

     

    Low-GI diet on the other hand, appeared to be the most healthy and sustainable in the long run compared to the low-carb diet, even though the effect on energy expenditure was not as pronounced, it was comparable nevertheless and more effective than the low-fat diet.

     

    Altering the components of your diet based on how your respond to different foods can make a significant impact on the body's energy expenditure and consequently affects weight loss/maintenance. Reducing fat from your diet doesn't necessarily translate into fat loss. A low-carb diet may be an effective and safe short-term boot camp solution for some but may also be harmful in the long run for others. A low-GI diet might not have the impact of the low-carb diet but it may be good for weight maintenance. Different people will respond to different types of food differently and you will have to find what's best for you. Remember, not all calories are created equal.

  • Sedentary life style can be detrimental

    Having a sedentary life style doesn't just make you unfit or gain weight. A recent study by Schmid and Meitzmann and published in the Journal of National Cancer Institute meta-analysed data collected from 4 million individuals including 68,936 cancer cases concluded that there is an increased risks of chronic disease and mortality rate associated with sedentary behaviors such as watching TV.

     

    The study found that each 2-hour per day increase in sitting time outside your normal occupation is associated with an 8% increased risk in colon cancer, a 10% increased risk in endometrial cancer and 6% increased risk in lung cancer. The increased risks in these cancers appear to be independent of physical activity. This means spending a large amount of time sitting down could be detrimental to health even to those who do regular exercise. Sitting at work seems to be a lot healthier than watching TV, given that you don't over do it. A 2-hour per day increment in sitting at work has been found to increase the risk of obesity by 5%, whereas each 2-hour per day increase in TV time is associated with 23% increase in obesity risks.

     

    The mechanism of which sedentary behaviors cause cancer is unclear. However, the authors of the study speculated that unhealthy eating habits, vitamin D deficiency due to a lack of sun exposure, weight gain from low energy expenditure and an increase in pro-inflammatory markers in blood due to prolonged sedentary life style maybe the main culprits. Colon cancer and endometrial cancer are obesity related cancers. Therefore, the increased risks of cancer caused by sedentary life style may work through similar pathways, even if you are not obese.

     

    People today spend on average 50 - 60% of their time in sedentary pursuits and we are in the middle of an obesity epidemic. On top of that, it's forecasted by the US National Cancer Institute that 1 in 2 men and 1 in 3 women will bear the risk of developing some form of cancer by 2050 in the US, doubling the current rates. Doing regular exercise can reduce the risk of mortality and chronic diseases. The world health organization (WHO) recognizes this and recommends adults to do a minimum of 150 minutes of moderate intensity exercise each week. What the WHO guideline doesn't address is the amount of time spent by people in sedentary pursuits, which will cause an increased risk in cancer independent of physical activity levels. It is therefore recommended that one should consciously limit the time spent watching TV and other screen-based entertainments. It is also recommended that children and adults should breakup their sitting-down periods, let it be at work or watching TV, traveling on a plane or during long distant driving with interspersing intervals of standing or short exercises. We as humans are not built to cope with sedentariness, start moving and life will prosper.

  • Types of exercise and fat loss

    One of the biggest issues of the modern society is the promotion of physical inactivity due to the advancements of technologies and social media, which intend to restrict our movements to as little as possible with the world on your fingertips. The physical inactiveness, along with bad diet and deteriorating daily routines are the main causes of the current obesity epidemic and the increasing prevalence of a number of lifestyle related diseases such as type 2 diabetes, stroke, cirrhosis, cancers and heart diseases. The World Health Organization (WHO) recommends an adult to perform a minimum of 150 minutes of moderate intensity exercise or 75 minutes of vigorous intensity exercise or a combination equivalent of both each week for health benefits. Recent research showed that one needs to perform up to 2-3 times the WHO minimum in order to achieve maximum benefits from exercise. Just doing the number may not be enough though. For many who want to trim, the type of exercise you do can make a difference in how quickly and effectively you can lose fat. One should always tailor their exercise regime based on their goals in order to achieve optimal results.

     

    Resistance training VS Aerobic training

     

    Research has shown that resistance training can improve lean body mass and glucose tolerance. The role of resistance training in fat loss is more debated, some suggested that resistance training could increase resting metabolic rate, hence induce fat loss. However, many of the studies to date found that resistance training doesn't significantly reduce fat mass irrespectively of the resting metabolic rate compared to the placebo. The effect of resistance training on fat mass is therefore inconclusive and resistance training is not effective for fat loss.

     

    On the other hand aerobic training (65% - 80% peak VO2, 150 minutes or 20km equivalent per week) decreases both body weight and fat mass significantly compared to resistance training and is more effective for fat loss.

     

    A combination of resistance training and aerobic training has been found to further promote fat loss in diabetic patients but not in inactive, obese individuals compared to doing aerobic training alone. However, combing resistance training and aerobic training has been found to significantly decrease waist circumference compared to resistance training alone.

     

    High intensity aerobic interval training VS continuous moderate intensity aerobic training

     

    High intensity aerobic interval training (~90% VO2) can increase fat oxidation in a very short period and can significantly reduce blood lipid levels compared to continuous moderate intensity aerobic training (VO2 65% - 75%). It also burns more calories than continuously moderate aerobic training and has a higher post exercise energy expenditure. High intensity aerobic interval training has been shown to require only 50% - 60% of the time to achieve the same gain in fitness compared to moderate intensity aerobic training. However, it is more prone to injury due to the increased intensity and harder for people to adhere to the training program.

     

    Interestingly, one recently study by Keating et al. 2014 published in the Journal of Obesity suggested that although high intensity aerobic interval training is effective at fat loss and improves fitness, continuous moderate intensity aerobic training is better at improving fat distribution independently of weight loss in previously inactive, overweight adults.

     

    Taken all the information together, the best way to lose fat and gain good body shape is to combine high intensity aerobic interval training with moderate intensity aerobic training and resistance training. Balance is key. Talk to your fitness professional to properly plan your exercise regime in order to prevent overtraining and injuries and to achieve maximum benefits.

  • 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 Is Targeted fat loss possible?

    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.

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