So bodybuilding, with its emphasis on eating right and regular exercise, can be considered a healthy practice. But some alarming recent research suggests that while we are building up our muscles, we may also be short-circuiting our longevity. It's important to point out that at present, the evidence for this is mostly circumstantial. It comes from animal research, and much of it may not apply to humans. So what are the habits of bodybuilders that may lead to decreased longevity?
The only tentatively accepted way to extend life is through calorie restriction. This entails lowering daily caloric intake about 30-40%. It appears to work in many animal species, but the evidence that it will extend life for humans is not definitive by any means. Still, based on the favorable animal studies, many humans have opted to use caloric restriction (CR) regimes in the hope of extending their life. Initial studies of these human CR self-experiments show some favorable changes in their physiology. They show low body fat levels, low resting insulin and glucose levels, and lower blood pressure and blood lipids. But they are also constantly cold, have no energy, and are very hungry. It takes an enormous amount of willpower to adhere to typical CR regimes. Most CR diet plans emphasize fruits and vegetables because of their lower caloric density. These CR humans also have lower levels of testosterone, although their IGF-1 levels don't seem to be affected by their lack of calories. They also usually look quite gaunt, lacking any semblance of muscularity.
In an effort to gain muscle, many bodybuilders still resort to the old "bulking up" technique, involving a high intake of calories. If the CR theory is true, then eating in this manner for extended times will take a toll on future longevity. On the other hand, the dieting phases of bodybuilding fit right in with CR theories. It's all a bit moot, since longevity scientists have calculated that CR is most effective when begun at birth! If you start a strict CR regime at age 48, and stay on it the rest of your life, you will extend your life by 2.8 years. That's a weak trade for years of being tired, hungry, weak, and yes, small.
Other animal studies show that restricting protein intake will extend life. Of course, eating a high protein diet is a staple of any bodybuilding nutrition program, since protein is the key for promoting muscle protein synthesis. In fact, it isn't protein that is the problem. The animal studies show that eliminating only one amino acid--methionine-- extend animal longevity by about 15%. But methionine is an essential amino acid, which means that it's a required nutrient. Completely eliminating it from a diet can spell trouble for humans.
Speaking of muscle protein synthesis, a key player in that process is a protein known as mTOR. Branched-chain amino acids, especially leucine, are known to promote mTOR activity, and by doing so,they upgrade MPS. But mTOR also plays a role in accelerating aging and even promoting the spread of cancers in the body. The good news is that mTOR can be controlled by promoting the release of another protein that opposes its actions: AMPK. You raise AMPK when you do aerobics, and using drugs such as metformin also boost AMPK. While AMPK blocks MPS through its interference with mTOR, it also boosts fat oxidation in muscle. A number of natural substances also boost AMPK, including resveratrol, caffeine, chromium, cinnamon, CLA, creatine, curcurmin, DHA from fish oil, garlic, and grape seed extract. Including some of these in the diet should offset the negative effects of mTOR without interfering with the MPS effects.
Bodybuilders often purposely raise their insulin levels, such as following a workout by consuming a simple carb and protein drink. Boosting insulin after the workout aids recovery by promoting amino acid uptake into muscle and also increasing the activity of the enzyme that synthesizes glycogen. Other bodybuilders inject insulin as an anabolic drug. The problem here is that lower insulin levels are associated with life extension. Studies of people who have lived to 100 or more show that such people always have both low resting insulin levels, as well as lower blood glucose levels. They also usually show lower levels of insulinlike growth factor-1 (IGF-1). IGF-1 is produced in the liver as a result of growth hormone release. It's also produced directly in muscle after exercise, where it exerts potent anabolic effects. Animals that lack receptors for IGF-1 live longer lives than normal animals. On the other hand, a lack of IGF-1 in human studies has shown an increase in mortality. Among other functions, IGF-1 helps to maintain both heart and brain cells. Growth hormone itself lowers oxidation at normal levels, but raises it when taken in larger doses, as is the practice of some competitive bodybuilders.
Then there is the resting metabolic rate. Some of the longest lived animals on Earth show low resting metabolic rates. These include certain mollusks known to live over 450 years, as well as tortoises that live to over 200. But other long-lived animals, such as bats and birds, have very high metabolic rates. Bodybuilders use supplements that boost metabolism for purposes of losing bodyfat, and some also use thyroid drugs for the same reason. Whether habitually boosting resting metabolic rate will limit longevity is anyone's guess.
When you add it all up the choice is clear: you can eat less protein, less calories and walk around small, weak, but healthy. Or you can continue the "risky" bodybuilding practices and look big, healthy and feel great. You may not live as long, but you'll get a lot more life out of those years compared to the pathetic CR cultists who are living on lettuce.
©,2013 Jerry Brainum. Any reprinting in any type of media, including electronic and foreign is expressly prohibited.
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This is a photo of Lisa Walford, who has been a CR advocate for many years. She is 50 years old in this photo.
