Bodybuilders are some of the leanest people around. At world class levels competitors will certainly have less than 10% body fat. So in addition to training, what kind of diet should help promote this level of leanness? Let's look at what Arnold Schwarzenegger advised in his 1984 book, Arnold's Bodybuilding for Men. I recently found a photocopy of p.197 in one of my old notebooks, which I have not looked at for 25 years. At the time of publication Arnold was just past his prime and had been arguably the best in the world during the 1970's. Here's what he had to say about diet:
"... [some bodybuilders] eat diets consisting of 50 to 70% protein, something I believe to be totally unnecessary.
"It is hard for me to convince them that what they ought to be eating is a basic, balanced diet, just like the one they were taught about back in health education class in school. I know they want something more exotic, but I can't help the way things are. That kind of balanced diet is necessary to provide the body with all of the essential nutrients it requires for the difficult and demanding training that bodybuilding involves.
"Here is my formula for basic good eating:
- Eat about 1 gram of protein for every 2 pounds of body weight.
- Eat no less than 60 and no more than 100 grams of carbohydrate per day.
- Limit your fat intake.
- Take a limited amount of vitamin and mineral supplementation just for insurance.
- If you want to gain or lose weight, vary your caloric intake -- and that variation should be mostly in carbohydrates, in the form of vegetables, potatoes and fruit.
"Earlier in my career, I believed that a bodybuilder needed to eat as much as 200 grams of protein a day in order to develop the maximum muscle mass. Since then, my research has shown me that body- builders do need more protein than the average per- son, but probably no more than around 100 grams, and certainly no more than 150. This gives enough protein for muscle-building, without adding any unnecessary calories to the diet. Non-bodybuilders, on the other hand, can easily get by on no more than 1 gram of protein for every kilo (2.2 pounds) of body weight."
Now, before looking closely at these recommendations, note the comment about school health education. Arnold would have been learning about this stuff in late grade school or junior high, but that would have been in Austria around 1960, most likely using textbooks published in the 1950's. The advice in those books I think would not likely have borne any resemblance to today's government food guides, but perhaps some industrious and resourceful reader will find out for us.
Now to the 5-point list of recommendations. The first thing to notice is that Arnold's advice on apportioning the three macronutrients (protein, carbohydrate, and fat) is quite specific on protein and carbohydrate, but extremely vague about fat. What does "limit" mean? Without a number this is meaningless, but we can get a reasonable estimate of how much this should be with some calculation (my interpretation of this point is that we shouldn't specifically add fats and oils to what is already in our foods. For example, trim your steak, enjoy the internal fat, but don't slather it with butter; don't drench your salad with oil; avoid fried foods).
So if I were to follow Arnold's advice, as a non-bodybuilder weighing 73 kg (160 lbs), I should get by on 70 grams of protein and 100 grams of carbohydrate. Considering a reasonably active lifestyle, I would need at least 2000 calories a day. We know that protein and carbohydrate contain 4 calories per gram, and fat has 9 calories per gram. So by Arnold's recommendation I will consume 70 * 4 = 280 protein calories and 100 * 4 = 400 carbohydrate calories. In order to get my 2000, I will need 1320 more calories from fat, or 66% of my intake! (The other proportions work out to 20% carbs, and 14% protein). He may not explicitly have said it, but he is recommending what would certainly today be called a high-fat diet!
In addition, point 5 is clear that carbohydrates will be the determining factor in how lean you get. It remains to be shown if this diet is healthy in the long run and if it would get results for most people. Considering the number of testimonials out there, and personal experience, I would definitely recommend eating like Conan!