CrossFit East Bay Power/Weight Challenge:
Macronutrient Metabolism; Fat Loss

From a typical nutrition textbook: "When you eat too much you get fat, when you don't eat enough you get thin, everybody knows these simple facts but nobody knows exactly how to account for them". This is an oversimplification with a lot of truth to it.

There are some folks (you see a lot of them at a climbing gym) who have a really hard time adding any muscular mass, and can, for all intents and purposes eat whatever they want in pretty much any quantity without gaining significant bodyfat. These folks are ectomorphs, skinny and often tall: the "98 pound weakling" of yore. They are also known as "hardgainers" and have a difficult time gaining muscle mass or getting strong.

On the other end of the scale is the endomorph, who easily gains fat mass, but generally can easily become strong. Almost all unlimited weight class Olympic lifters seem to be of this type.

Those who are smart enough to have picked the right parents are mesomorphs, like pretty much all of the top males and most females at this years CrossFit Games. They are lean and muscular, a cultural ideal.

These body types can be mixed: meso-endo and meso-ecto. It may be that the different body types have different insulin sensitivity: Dr. Barry Sears in The Zone, thorizes that about 25% of the population have a poor reaction to carbohydrate leading to obesity when consuming a high-carb, especially high glycemic carb, diet. He postulates that significant genetic adaptation may have taken place in about 25% of the population that enables them to eat a high-grain diet with little or no ill effects (they stay skinny and don't get tired even if they eat giant pasta meals). Finally, everyone else is somewhere in the middle: his Zone DIet is designed to work well for all the types.

So what happens in the body to the carbohydrate, protien and fat we eat? It is pretty complicated, but here is what you need to know for fat loss or muscle gain. Please bear in mind the human body is an almost incomprehensibly complex machine: what follows is a vast oversimplification. Additionally metabolism is not fully understood, so this represents what I think is the best understanding we have today.

Our bodies are constantly burning fuel, simply to exist, even when asleep. this is called basal metabolism. Generally this is fueled by a 50/50 mix of fat and glycogen (the product of carbohydrate). Any food over and above metabolic need is converted to bodyfat, or excreted. During moderate-intensity aerobic work, this ratio switches to favor fat burning perhaps 70/30. During intense exercise (short metcon) the body is burning through glycogen at a blistering rate, preferring nearly 100% of energy needs from glycogen. Intense work of this type increases the bodies metabolic need quite a bit subsequent to the actual work, so additional bodyfat may be burned afterward. So given adequate glycogen, fat can be burned through exercise and bodyfat can be decreased. Very little, if any, muscle wasting occurs as long as nutrition is adequate.

However, when we intentionally deprive the body of calories (fasting) the following comes into play: the body can actually power itself quite well for up to about a day on stored glycogen and fat, which are turned into glucose and fatty acids and flow into cells to power them. (this is assuming you are not doing Murph in addition to fasting), however, the brain needs glucose to work, and in the absence of glycogen, the body will begin breaking down lean muscle tissue to create glucose, a metabolically very expensive process. This is why starving yourself will not work. Anything below 1500 cal a day for men and 1200 cal a day for women, on average, is going to result in significant muscle loss. And this is average: most CrossFitters have more muscle and more metabolic demand.

So: without even considering the protein requirement we see that just the right amount of deficit must be created to lose fat and not muscle. One reasonably simple way to get it right is the Zone Diet, the CrossFit diet of choice. Find your block count, and then take 1-4 blocks off of that depending on how fast you wish to lose weight. Of course the more you take off, the more danger you are in of losing muscle. It is ESSENTIAL to weigh and measure everything on this diet, certainly for the first few weeks.

Next: The Hardgainer