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Posted 09 August 2012 by Adam Bisek

Fat Loss Physiology:


Why "Diets" Don't Work

Fat Loss Physiology: Why "Diets" Don't Work

Why do we get fat? And when we try to lose it why do most fail or revert back? The answer lies in a simple analogous adventure into our prehistoric past. If we look at how our caveman and women ancestors lived and subsisted, and how our physiology seeks homeostasis, it is easy to see how diets are often unsuccessful in the long run.

The human body and its checks and balances are meant to keep us at just the right weight and body fat. Our fat cells, and to a smaller extent the cells in the lining of the stomach, secrete a hormone called leptin. That's right, our fat is an active part of the endocrine system. When we become lean our fat is lower and subsequently less leptin is produced and sent to the brain, and more specifically the hypothalamus. When this happens the hypothalamus decreases thyroid activity, down regulating our metabolism and also sends out hormones such as ghrelin and neuropeptide Y (NPY), which make us hungry. Think about it, if we go back to our caveman, it makes sense to decrease his metabolism in famine, and increase his hunger to seek his next meal. His body wants him to get back to a body fat that will support famine or the long winter.

The inverse happens when our body fat increases. Increased body fat increases the leptin signal to the hypothalamus and to this it increases metabolism via the thyroid, and decreases hormonal signals of hunger. Although our caveman needs to have enough body fat to survive the next famine, his body also realizes he needs to be lean enough to run away from the occasional tiger.

↓ Fat = ↓ Leptin = ↑ Hunger Hormones + ↓ Metabolism

↑ Fat = ↑ Leptin = ↓ Hunger Hormones + ↑ Metabolism

So how is it that obesity is an issue in the western society? Much like the body becomes resistant to insulin in Type 2 Diabetes, it also becomes leptin resistant. This is due to many things such as a sedentary lifestyle, over consumption of processed carbohydrates, elevated triglycerides, chronic stress, and toxicity just to name a few. This sounds a lot like the lifestyle of many Americans. Essentially the hypothalamus does not receive the signal despite the over abundance of fat and subsequently leptin. Luckily reversing leptin resistance can be accomplished by paying attention to the aforementioned lifestyle factors. Maintaining regular physical activity, increasing whole food consumption in contrast to processed foods, dealing with stress, decreasing alcohol consumption, and investigating and rectifying possible sources of toxicity will go a long way in dealing with leptin resistance.

So getting to our main point; why do "diets" fail? First it's because the modern conception of diet is incorrect, and means nothing more than a way of eating or a lifestyle. Essentially the same physiological mechanism that kept our caveman the right body fat still exists in our bodies today. When we begin to go into famine, which in modern day is merely caloric restriction through decreasing food consumption, our bodies’ natural mechanisms sense this over time and decrease metabolism. To compound this dieters try to create a caloric deficit by increasing activity, and in many cases this takes the form of long duration aerobic activity, although this may not always be the case. Now think about it, if our caveman were in famine would he go for a jog to expend energy, or conserve it? To this our body has to release cortisol, a stress hormone that helps liberate fat, glucose, and protein from muscle to provide us with energy. The only bad thing is that this hormone also likes to deposit fat in the abdominal region when elevated chronically! While this is all happening our body is in a net protein loss, which leads to loss of muscle. To pile it on our body also begins to send out this hunger signals ghrelin and NPY as it senses famine, and also because our stress hormones do a great job at stimulating NPY release. NPY is an interesting hormone because it makes us crave sweet things, not so bad for our caveman who would find some berries, but now those berries have turned into a snickers bar from the closest vending machine.

So that's where the common day "dieter" is left. Sporting a decreased metabolism, increased hunger for bad food options, increased circulating stress hormones, and decreased muscle mass. Not a good situation for maintaining the possible weight lost. The truth is that it's not about a number, it's not about weight loss, it's about fat loss. It's not about the mindset of a "diet"' but a change in a lifestyle. Successful and maintained fat loss is achieved slower and through making changes in lifestyle to increasing physical activity, making better food choices, decreasing stress, and being practical about what can be achieved.

When it comes to the traditional approach to fat loss, there is a lot left to be desired. Long drawn out aerobic sessions are not the way to go. While maintaining aerobic fitness is important, one can do so by maintaining a progressive resistance-training program that includes shorter more relatively intense bouts of activity. This maintains muscle mass and decreases the chronic stress response brought about by long duration steady state aerobic sessions. In addition to this a grocery list that includes plenty of sources of protein, fruits, vegetables, and some nuts, seeds, and healthy oils, while staying away from more processed foods found in boxes and bags will go a long way. And finally, use the trusty SMART goal model to establish specific, measurable, attainable, realistic, and time-oriented goals. Getting social support from friends and family, as well as accountability from a fitness professional will also better your chances of taking of the fat for good.

I hope this journey to ancestral homeostasis was enlightening or will at least save you or someone you know from falling into the traditional approach to fat loss. Until next time, get Big, be Strong, keep Fit, and stay Healthy!

Written by Adam Bisek

 

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