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Weight Loss

  • Sleep and weight loss

    Sleep is an important modulator of neuroendocrine function and glucose metabolism. It has been reported that the worldwide prevalence of obesity has doubled since 1980, with women more likely to be obese than men. This obesity epidemic has been paralleled by a trend of increasing prevalence of sleep loss in both children and adults in the modern society. We are sleeping a lot less than we were a few decades ago and are paying the price for it. Significant amount scientific evidence has indicated that poor sleep quality and sleep loss can cause endocrine alterations, including decreased insulin tolerance and sensitivity, increased level of cortisol in the body in evenings, increased level of ghrelin, decreased level of leptin, and increased hunger and appetite. There is a direct association between increased BMI and sleep loss. Children and adults who are short sleepers are at a higher risk for weight gain and obesity. In addition, the dysregulation of the neuroendocrine control of appetite and the alteration of glucose tolerance in people who are not getting enough sleep exposed them to an increased risk of getting diabetes later in life.


    So, how much sleep is enough? Well, it really depends on the individual and your age group. One may feel properly rested after 6 and half hours of sleep while others may need 9 hours of sleep to feel rejuvenated. The average basal sleep need for a healthy adult is around 7-8 hours per night. This is discounting all the sleep debt that one accumulates due to previous sleep loss, which may make you feel tired even after a few nights of good sleep unless the debt is paid.


    Many of us work very hard to keep our weights down but sometimes we forgot that basic routines in life such as sleep could have a far greater impact on our body and health than the extra 2km you run on the treadmill the other day. Getting enough sleep is probably the easiest, cheapest and most productive way of setting yourself up a good foundation to a healthy and lean life.

  • 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.

  • Water fad

    Functional drinks are the new fad, do they really live up to the hype? In this article we examined the science behind some of the claims made by the manufacturers of 3 popular types of drinks: the oxygenated water, vitamin water and coconut water.

    Oxygenated water

    Let's start with oxygenated water, in some places it's called hyper or super oxygenated water, as all water is more of less oxygenated. One may ask: can oxygen supplementation improve exercise performance? Yes. It was observed that the BREATHING oxygen DURING exercise could enhance athletic performance (Wagner 1996, Annual Review of Physiology). But the timing of the oxygen supplementation is important, breathing 100% oxygen before or after exercise or during exercise intervals does not aid recovery or enhance performance (Robbins et al. 1992, Medicine and Science in Sports and Exercise). This means that, assuming drinking oxygen is the same as breathing oxygen, you will have be drink the water while exercising. How much oxygen do hyperoxygenated water contain? Well, certainly not 100%

    The solubility of oxygen in liquid is very low, it is related to temperature and the pressure at the air-liquid interface (the surface of the water). The oxygen content of bottled water can thus be increased by increasing the pressure inside the bottle. However, once the pressure drops, i.e. the opening of the bottle, the water will start to de-gas quite rapidly, much like carbonated soft drinks. The oxygen content inside the water will consequently fall to normal levels, similar to that of found in tap water. One has to open the bottle to drink the water, therefore even if the oxygen content of the water inside the bottle is significantly higher than in normal water, its oxygen concentration will be greatly reduced by the time it reaches your stomach. One study measured the oxygen concentration in 5 different brands of hyperoxygenated water in SEALED bottles and compared that with the oxygen concentration of normal tap water. It was found that 4 out of the 5 brands did indeed have a higher oxygen concentration as compared to normal tap water (3-9 times higher depends on bands), however one was the same as tap water (Hampson et al. 2003, JAMA). There seemed to be quite a bit of inconsistency in quality between different brands. The highest oxygen concentration in the hyperoxygenated water tested as determined in the Hampson study was only 8%, which is much lower than the 21% oxygen content of the air. This means each litre of hyperoxygenated water contains around 80mL of air, whereas a normal human can inhale roughly 100mL of oxygen with each breath. No wonder Piantadosi proclaimed in the British Journal of Sports Medicine: "A breath of fresh air contains more O2 than a litre of hyperoxygenated water".

    One may argue that the extra oxygen in water can be absorbed directly into the body hence have health benefits. That is not true, in fact, there is no conclusive evidence suggesting that oxygen in water could be absorbed by the body. Even if the oxygen did somehow enter the blood stream via the intestines, it would probably enter the veins rather than an artery, which will then be on its way to get re-oxygenated by the lung. It was postulated that for ingested oxygen to have any potential effect on a normal person's systemic oxygen delivery, one would need to provide 250mL of rapidly absorbable oxygen per minute (Piantadosi 2006, British Journal of Sports Medicine). To be able to achieve that, you will have to drink over 3 litres of hyperoxygenated water that contains 9 times higher concentration of oxygen than tap water per minute, and hoping that all oxygen in the water will get absorbed into the blood streams. That's going to be a lot of money spent on water, per minute ;-)

    Now, all theories aside, can oxygenated water improve your exercise performance and recovery in a practical setting? The answer is no. There's currently no scientific evidence supporting the notion that consuming hyperoxygenated water can improve exercise performance or aid recovery (McNaughton et al 2007, International Journal of Sports Physiology and Performance; Wing-Gaia et al. 2005, International Journal of Sports Nutrition and Exercise Metabolism; Leibetseder et al. 2006, International Journal of Sports Medicine). It's suggested that the amount of oxygen contained in the water is too low to have any impact on the plasma oxygen levels as hemoglobin (the iron-containing oxygen transport protein in red blood cells) is usually saturated (or close to being saturated) with oxygen during breathing (Jenkins et al. 2002, Medicine and Science in Sports and Exercise). On top of that, the oxygen in the water is likely to be consumed by the cells in the gut before they had any chance of reaching the blood or muscles (Willmert at al. 2002, Journal of Exercise Physiology).

    So, what can hyperoxygenated water do? It's good for hydration, just like normal water. Drinking hyperoxygenated water does not have any adverse effects on liver, blood and immune system (Gruber et al. 2005, Clinical Nutrition). Interestingly, studies found that the consumption of hyperoxygenated water could cause a temporary raise in oxygen radicals in the body (Schoenberg et al. 2002, European Journal of Medical Research; Gruber et al. 2005, Clinical Nutrition). This slight raise in oxygen radicals only lasted a short period and only happened to people who don't consume hyperoxygenated water regularly. No potential health implications were mentioned in any of these studies. Hyperoxygenated water is safe for human consumption.

    Vitamin water

    I have to say I liked the idea of vitamin water, it's a neat concept. However, after picking up a few bottles of different flavored vitamin water from the supermarket, and carefully examined their nutritional contents, I started having doubts about whether this is a good idea after all. Here are my reasons:

    • Regardless the formulation, vitamin water generally contains a limited number of key vitamins and minerals, and a lot of sugar. Each 500mL bottle contains around 30 grams of sugar, this almost equal to the amount of sugar found in a can of regular coke. If you opt for the sugar-free version, please refer to the aspartame article in the previous edition of this magazine before proceeding further. One may argue that vitamin water is a form of sports drink, and sugar can help with exercise performance (please refer to Are sports drinks beneficial during workouts in the Oct/Nov 2012 edition of the magazine). Of course, having carbs (in the form of sugars) is somewhat important, however, in order for the drink to function as a sports drink, one should also contain a good amount of electrolytes, such as potassium, which is noticeably absent in some of the formulations. Make sure to pick a formulation that contains a good dose of potassium if you wish to use it as a sports drink.
    • One other concern I have is the quality and the stability of vitamins in the drinks. There are 2 types of vitamins, water-soluble vitamins, including vitamin B and vitamin C; and fat-soluble vitamins, including vitamin A, D, E and K. Both types of vitamins tend degrade after dissolved in liquid, albeit at different rates. One study investigated the stability of water- and fat-soluble vitamins in vitamin enriched liquid serum and found that after one year of storage at -20 degrees C, up to 30% of the water-soluble vitamins were degraded whereas over 50% of the fat-soluble vitamins were degraded (Ihara et al. 2004, Journal of Clinical Laboratory Analysis). There is no guaranty of the conditions where the vitamin water was stored and transport before they reached the shelves and thus no real assurance of the quality and stability of the vitamins. Indeed, currently available studies investigating the efficacy of the vitamins in vitamin waters only studied the water-soluble vitamins. One study investigated the absorption of vitamin C and B in a commercially available vitamin water and compared to that of the vitamins contained in mixed meals, and found the blood vitamin levels to be identical after consumption (Kalman et al. 2009, International Journal of Food Science and Nutrition). Another study used self-made vitamin C and iron-fortified water and found that it can improve people's nutritional status after 5 months of consumption (Rhoca Dda et al. 2011, Food and Nutrition Bulletin).

    Overall, I think the vitamin water currently available on the market is not that dissimilar to the common soft drinks, minus the fizziness. If you want nice tasting water that has a good range of nutrients and antioxidants without all the artificial additives, try fresh juice.

    Coconut water

    Coconut water, or more scientifically but less appealingly, coconut liquid endosperm has been dubbed by some as one of the worlds most versatile natural products. When I say coconut water here as a drink, I mean the clear, natural, unprocessed, unsweetened liquid taken directly from a fresh coconut, not to be confused with the white coconut milk commonly used in cooking in some of the South East Asian countries. Natural coconut water contains a huge variety of vitamins, amino acids, minerals, fibers, with little fat (less than 0.2%), protein (less than 0.75%) and relative low amount (less than 5%) of sugars (contains a mixture of glucose, sucrose and fructose). The energy content of coconut water is around 79kj per 100g. The sodium content of coconut water varies depending on the growth environment and the age of the coconuts, it can range from 1.75mg/100g of water (results from 1 study) to 105mg/100g of water (results from 3 studies). Many of the nutrients are only found in low levels in coconut water, however, it contains a large amount of potassium, at over 200mg per 100g of water (Yong at al. 2009, Molecules). There is more potassium in 100g of coconut water than that of in a common 600mL (roughly 600g) sports drink. It has been suggested by some that certain contents in coconut water, when used as a pure agent in high doses may have anti-aging, anti-cancer properties in fruit flies or mammalian cell lines. However, I have yet to see any concrete proof to show that the consumption and/or application of coconut water have any such effects in humans.

    Coconut water has been found to be able to effectively aid rehydration after exercise induced dehydration and support physical performance in a similar fashion compared to that of a commercially available carbohydrate-electrolyte sports drinks (Kalman et al. 2012, Journal of the International Society of Sports Nutrition). Another recent study evaluated the hypoglycemic and antioxidant effects of coconut water extracted from mature coconuts on diabetic rats. It showed that diabetic animals treated with the coconut water had lower blood glucose levels and reduced oxidative stress (Preetha et al. 2012, Food and Function). Of course, rats are very different to humans and a positive result obtained on rats does not mean it will translate into humans, in fact, in many cases it doesn't. It would be nice to to see similar studies to be conducted on human patients as here is currently no study that demonstrates drinking coconut water has any tangible benefits on human health, other than providing hydration and supply electrolytes.

    So all in all, I think coconut water is a healthier alternative to artificially flavored sports drinks, at least it's natural. However, some natural coconut water contains more sodium (salt) per 100mL than sports drinks. We already ingest more than enough salt from our diet and having too much salt can lead to a number of health complications. In addition, the trace amount of vitamins and minerals other than potassium contained in coconut water means that it's not a viable replacement for you daily meals. It's also not very cheap in Australia. However, if coconut water is your thing, make sure the sodium content is low and the drink is not artificially flavored, otherwise, it will be no better than a flavored sports drink.

    The purpose of this article is not to "debunk" the myths or glorify benefits of the chosen functional drinks. What I hope to achieve, is to help you looking at products like this in a more rational manner, and to understand that there are no shortcuts for living a healthy life.

  • 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.

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