Columnist reveals the truth about metabolism

Kyle Kranz

Kyle KranzRunning on the white Line

There are many myths in the health world, and one that may be the most hassle to people attempting to lose or maintain weight is the theory that eating smaller, more frequent meals will raise your metabolism.

Metabolism is simply the chemical and physical properties in your body that build and destroy tissue and release energy, thus creating heat through thermogenesis. Our metabolism increases and we burn more calories when we are exerting ourselves, such as walking to class, studying (your brain uses a lot of energy), or exercising. When at rest we burn slightly less calories, but they are still expended.

The theory is that many small, frequent meals will keep your metabolism going strong. However, it has been shown in controlled settings, that when you match caloric and macronutrient (protein, carbohydrate and fat) intake, the metabolic difference in many smaller meals compared to few large meals is practically zero. There is not going to be any change in thermogenic differences. It is important to remember when dieting to lose weight that when you eat, it takes a lot of energy to digest the food. That is the reason why starving yourself, skipping meals, and cutting back on too many calories will not so simply result in weight loss. Larger meals will have a larger thermogenic effect compared to the smaller meals, but it will equal out over the course of a day. We are not cows necessarily meant to be grazing all day. Do not tease yourself with that little 100 calorie pack, if you are hungry go ahead and eat a meal.

There is also a myth that our metabolism slows down as we age. Well unfortunately you can tell your parents that age has very little to do with it! Increases in body fat through life are a trend that has been shown to be a function of inactivity and loss of muscle, not simply a lowering of the metabolic rate. A study at the University of Minnesota found that the energy requirements of fat-free body mass were nearly constant among age and sex. It did not matter if the subject was a 20-year-old male or 60-year-old female; everyone burned about the same amount of calories per pound of lean mass at rest.

So why then, do we gain weight as we age? A big factor is that as we age, our muscle mass decreases. This results in a loss of metabolism since muscle is active tissue requiring oxygen. This may be the largest factor in a lowering metabolism.

Also, nearly as influential is the fact that as we age we seem to become less active (which attributes to the muscle loss). Maybe you get an 8 to 5 desk job that’s a lot less walking around than you are likely doing now between classes and home. People work eight or nine hours, five days a week and may not feel like going for a run or swim after work anymore. I visited and found that if I were to keep the same caloric intake but go from a moderately active lifestyle to a sedentary lifestyle, my basil metabolic rate would decrease by about 200 calories each day, which would result in a gain of 18 pounds over a year!

It becomes fairly obvious then, that to keep that metabolism up you need to follow the example of the 70-year-old gentleman playing basketball at 6 a.m. at the Wellness Center. That activity will help hold onto your lean muscle mass and burn calories, along with many other physical and mental benefits. If you are happy with where you are at diet-wise, then keep at it if it’s working. However there is no need to force yourself into consuming smaller meals if weight loss is a goal of yours. A healthy eating pattern along with exercise is the best path to follow for a fit body.

Kyle Kranz is a senior nutrition major at SDSU. Contact him at [email protected]

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