Drowning in Information, Starving for Knowledge

So every once in a while I'll hop on Yahoo's question and answer boards, in the diet and fitness section obviously, to check out the questions and throw out some answers. It is a valuable exercise, as it always reminds me that the vast majority of people out there don't have a clue about fitness and weight loss.

This is generally no fault of their own. We are bombarded daily with so much misinformation on fad diets, magic diet pills and supplements, and infomercial junk like the 'Ab Lounger' and anything by Body by Jake, it isn't surprising that people would be confused.

While just about all of the questions on these boards are some flavor of 'How can I lose weight fast', a surprising number have to do with trying to lose weight by fasting. Fasting, or starving yourself, is the ultimate way to destroy your metabolism and end up making yourself fatter in the end.

Hopefully none of you reading this would even consider this as a legitimate way to lose weight, but just in case, here is a copy of my answer to someone asking how she should go about fasting in order to lose 17 lbs.

Enjoy.

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It is very easy to lose weight by fasting. Unhealthy, and in the end counterproductive, but easy. You starve yourself, you lose weight. But, you should know what happens when you do this first.

When you starve yourself (which is what fasting is), you inhibit your body's ability to burn fat. You need to remember that calories are simply a unit of energy, and your body needs energy every day to survive. So, when you don't eat, about 300,000 years of evolutionary drive kick in and your body goes into starvation survival mode. It sets of a chain of processes all designed to slow down your metabolism (the rate at which you burn calories) because your body always wants calories in to be equal or greater than calories out. So your brain starts sending signals to your thyroid to slow things down.

Then, you need to understand that body fat is your body's long term energy survival source. So, wanting to survive as long as possible, your body will do whatever it can to hold onto body fat. This is obviously not what you want, but it's what happens.

Your major organs (brain, heart, etc) can't use stored fat for the energy they need, they can only use glucose, which is what carbs break down into thru digestion. Since you are starving yourself and not supplying your brain with glucose, your body has another survival trick. It creates its own glucose.

Unfortunately, it does that by breaking down muscle mass into the component amino acids that make up muscle protein. It then converts these amino acids into glucose to feed your brain, since you apparently won't do it with food. So now you are losing muscle mass.

Since muscle is the engine where your body burns fat for energy, you now have less of it, and burn fewer calories all day. This is another way your body slows down your metabolism to survive.

Eventually, you can't keep starving yourself, so you start eating again. Unfortunately, you've cratered your metabolism so when you start eating, you gain any weight you lost back very quickly. The bad thing now is the fact that while some of the weight you lost was fat, a lot of it was muscle mass and water. When you gain it back, it all comes back as fat.

Will you lose your 17 lbs? I don't know. But, what I do know is that the weight you will lose will be a combination of fat, muscle, and water. And whatever weight you lose, you will gain back quickly, all in the form of ugly fat.

So in the end, your starvation diet will make you fatter than when you started. This is the definition of yo-yo dieting.

Hope that helps,
Dave