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Gang of Five
Feb 2001

By Dr. John M Berardi, Ph.D.
First published at www.t-mag.com

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But John, FLEX said to . . .

Q. I just read in FLEX magazine that I should be taking in 3 grams of carbs per pound of bodyweight in addition to 1.5 to 2 grams of protein, daily. Wouldn't most average 200-pound lifters get fat eating 600 grams of carbs a day?

A. Although this question seems relatively simple to answer it isn't. There are so many physiological and individual factors that determine which diet each person should follow that I could write several articles just to answer this one question. Don't worry though, I'll spare you the grief of my excessive ranting.

To answer your question you've gotta approach eating first from the simplest perspective; the calorie balance perspective. Assuming you're a 200lb bodybuilder, the recommendations in FLEX are to eat 600g of carbohydrates and 300-400g of protein daily. If we assume you can manage 1.5g/lb for protein, we're talking 300grams a day. Add those up in terms of calories and you're looking at 3600 calories per day. Since the diet they are recommending is high in carbs and protein, I'll assume it would also be low in fat; maybe about 10% fat. So this would mean you would get an additional 50g of fat in the diet. Tallying these numbers up you get about 4050 total calories per day (60% carbohydrate, 30% protein, 10% fat).

So the next question to ask is "will 4000 calories per day make me fat?". To answer this one, you have to know several other things; what your body composition is, what your metabolic rate is like, and what your daily calorie expenditure is. Let's tackle them one at a time.

1) If your body fat is 15% (the average for 20-30 year olds), that means you have about 170lbs or 77kg of lean mass.

2) Calculate energy needs:

a. Using this formula [RMR=500+22(lean mass in kg)] you can determine your resting metabolic rate.
b. Then, by taking this number, you multiply it by 1.2 if you lead an inactive lifestyle, 1.5 if you only do light work during the day, 1.6 if you do moderate work, and 1.9 if you do manual labor. Remember, these factors do not include your workout, so if you work at a computer all day long, you multiply by 1.2. Now you have (RMR with activity factor).
c. Next you would take your original RMR and multiply it by 0.10. Add this number to your RMR with activity factor to get (RMR with activity factor + thermic effect of food). This would represent your calorie needs on non-training days.
d. On training days, an additional 500 calories or so would be needed to make up for the workout.
e. Eating this amount of food +/- 10% should keep your weight constant. Eating more should make you gain, eating less should make you lose.

3) Calculations:

a. A 15% fat; 200lb guy who works in an office building will need about 2900 calories on non-training days and 3400 on training days.

So, as you can see, the FLEX recommendations may make him fat indeed. He will definitely gain some muscle along the way too. Remember, though, if his calorie needs were in the neighborhood of 4000, due to a more active lifestyle, then no, the FLEX diet will not make him fat and might actually cause weight loss. But since calorie balance is only the simplest piece of the puzzle, we have to go one step farther.

Since I'm certain the FLEX recommendations were designed for weight gain, the second perspective we have to consider is that everyone is different and that different high calorie diets may produce different ratios of fat to muscle gain. For instance the diet high in carbs like this one (60% carbohydrate, 30% protein, 10% fat) may pack on muscle with minimal fat gain in some guys while others will look bloated, smooth and sorry. On the other hand, a diet higher in fat and lower in carbs (40%protein, 30% carbohydrate, and 30% fat) may lead to better muscle definition and fullness in some while plain old fat gain in others. So what's crystal clear is that different weight lifters need different diets.

How does one choose which diet is best for them besides experimentation (which, incidentally, is the best darn way to choose which diet is best)? Well, that's about as clear as a muddy lake. One of the keys, however, could be insulin sensitivity. If your body is very highly insulin sensitive (meaning that it releases less insulin per unit glucose eaten and absorbed) then your muscle gain to fat gain ratio will probably be higher on the higher carb/lower fat diets. If your body has very poor insulin sensitivity (meaning that your body overproduces insulin per unit glucose eaten and absorbed) then your muscle gain to fat gain ratio will probably be better on lower carb/higher fat diets.

Some people suggest that simple things like whether you get tired after a carb meal or whether you have an apple shaped fat distribution can give you subtle hints that you are have poor insulin sensitivity but I think these measures are too subjective. I know of a few objective measures and will be discussing them in an upcoming article. Until then, don't be afraid to start experimenting. Again, this is probably the best way to figure out what's best for your body type anyway.