Eat meat and vegetables, nuts and seeds, some fruit, little starch and no sugar. Keep intake to levels that will support exercise but not body fat.
–Greg Glassman, “What is Fitness?,” CrossFit Journal (Oct. 2002) pg. 1
Who Needs to Worry About Food Quantities?
Some people (many of them CrossFitters) are dedicated athletes who are already at the peak of their performance, whose bodies are already at an ideal weight and body fat percentage, and who are already committed to eating a diet composed exclusively of high-quality foods (i.e. a Paleo-Diet). Such people probably don’t need to worry about food quantities. They just need to continue eating clean and training hard.
The rest of us may need to be a bit more thoughtful about how much we eat. Besides learning to eat the best quality foods, we also need to learn how to eat those foods in the right proportions so that we can meet our goals, whatever they may be (e.g. athletic performance or weight loss).
Recommended Daily Intakes (RDIs) for Macronutrients
With nutrition, as with fitness, CrossFit espouses a contrarian philosophy. You are advised to more or less disregard the official US “Reference Daily Intake” guidelines promoted by the FDA and printed on every food label in the country.
The official CrossFit Mainsite Nutrition Guidelines promote the approach to food quantities found in the “Zone Diet” system of Dr. Barry Sears (see the nutrition links for more information). Others prefer the “Primal Diet” approach of Mark Sisson, or the “Protein Power” diet of Michael and Mary Dan Eades; still others simply prefer the Paleo-diet theories and guidelines of Loren Cordain. (Again, for information on these diet theories, see the links).
These dietary theories are all different, but they share in common a certain number of typical features. They all promote a diet that is richer in protein, higher in fat, and lower in carbohydrates than the official RDIs of the U.S. government.
Daily Protein Requirements
The foundation of an athlete’s diet is protein sources. To build and maintain muscles, and to keep all your body’s tissues and cells healthy, your body requires protein. Studies show that increased dietary protein leads to a growth in lean body mass.
Ideally, an athlete’s protein needs should be met by eating protein from animal sources (such as beef, lamb, bison, chicken, seafood, and eggs). Whey and Casein protein (derived from milk) is acceptable as a supplement. Soy and vegetarian or vegan protein sources are less highly valued.
But however you get your protein, when you calculate your ideal total daily intake of food you will start with figuring out how much protein you need.
The official US RDIs for protein suggest that most people, on a 2000 calorie diet, need only 50g of protein daily. But experience teaches CrossFitters, athletes, and weightlifters that an athlete’s body requires far more protein than these official RDIs would suggest.
Credible sources recommend around 0.7 to 1 gram of protein per pound of lean body mass, per day. Some authors, such as Robb Wolf, recommend more protein than this, on the order of .7 to 1 gram per pound of total body weight, per day.
Thus, a 175 lb male athlete with 15% body fat needs between 105 and 175 grams of protein per day. A 120 lb female athlete with 20% body fat needs between 70 and 120 grams per day.
In simpler terms, the male needs between 15 and 25 oz. of lean meat per day, and the female needs between 10 and 17 oz. of lean meat per day.
If our hypothetical athletes divided this amount into 3-4 meals per day, the male would be eating between 4-6 oz of meal per meal, and the female would be eating between 3-4 oz of meat per meal. These are actually small portions, leaving plenty of room on the plate for high quality carbohydrates.
Limiting Daily Carbohydrate Intake
Another thing the contrarian dietary theories agree upon is the need to limit one’s intake of carbohydrates, especially sugars and starches: the “refined,” “complex,” “dense” or “high glycemic” carbohydrates. The Zone diet, and the “Primal Diet,” and the “Protein Power” diet all promote a “low carb” diet of one kind or another.
The reason we eat a “low carb” diet is simple: eating too many carbohydrates keeps your insulin levels too high, with the result that you store fat instead of burning it. Limiting total dietary carbohydrates can thus help one lose unwanted pounds of fat, and help one to draw on fat stores for fuel during daily activities and exercise.
Furthermore, most of the metabolic diseases that plague modern human beings seem to be in some way linked to elevated insulin and an associated problem it contributes to: systemic inflammation. For more information on insulin, systemic inflammation, and disease, try a google search or read the books of Loren Cordain and Barry Sears (see the links page).
Again, in the case of carbohydrates, the Paleo-Diet will get you most of the way there. When we eliminate added sugar (including Evaporated Cane Juice, Honey, Agave, Maple Syrup, Molasses, etc.), and eat little to no grains and other starchy foods, we almost inevitably drastically limit the number of carbs we eat per day. In fact, if you limit yourself to eating only low glycemic carbohydrates such as leafy greens and vegetables, it is almost physically impossible to eat too many carbohydrates. The only thing that Paleo-dieters have to watch out for is eating excessive quantities of sweet fruits; as Glassman suggests, eat “some fruit.”
As a general guideline, let us suggest that a CrossFit athlete should be eating veggies at every meal — if at all possible. If you eat starches and fruit, these should be consumed after workouts or training or periods of high activity.
A typical plate of food should contain a small piece of meat and a large portion of vegetables.
In the classic “Zone” diet of Barry Sears, it is recommended that people eat 4 grams of carbohydrates for every 3 grams of protein. Robb Wolf recommends more like 2 grams of carbohydrates to every 3 grams of protein. It all depends on your own preferences, weight loss goals, and metabolic response to carbohydrates.
To look again at the diets of our hypothetical 175 lb male and 120 lb female athletes, the male would eat anywhere from 70 to 225 grams of carbs per day (depending on his needs), and the female would eat between 45 and 150 grams per day (depending on her needs).
Primal Diet guru and author of The Primal Blueprint Mark Sisson suggests that Primal eaters should consume no more than between 50 and 150 g of carbohydrate per day.
Either way, this is a lot less than the FDA’s RDI as found on food labels, where the government recommends 350 g of carbs for a 2500 calorie per day diet. (But note, the medical establishment’s food and nutrition board actually recommends only 130g of carbohydrates per day; see here for details).
Finally, FAT. People hate fat, love fat, and love to hate fat. The FDA and AHA encourage us to avoid fat in our diets, and recommend between 65 and 80 grams per day. On the other hand, the medical establishment has made “no determination” with respect to how much fat we should eat.
The ugly truth is this: even though all Americans “know” that fat is so “bad for them,” actually science has failed to show that dietary fat has anything to do with obesity or heart disease. Dieticians have been telling everybody to limit the fat in their diets; so people go out and buy “low fat” cookies and ice cream bars. We now know that eating fat doesn’t make you fat or sick, and avoiding fat doesn’t make you thin or well. The reason to avoid ice cream is the dairy, and the sugar, not the fat. Taking out the fat doesn’t make it healthy. Taking out the fat just makes it suck.
Experienced CrossFit athletes know that, besides being tasty, fat provides an outstanding source of fuel for the body (without impacting your insulin levels and use of stored fat for energy). Furthermore, science has demonstrated that the so-called essential fatty acids, especially Omega-3 fats, are necessary for the functioning of many tissues and hormones in the body.
The bottom line is: you should not fear fat. Even the modern medical establishment is increasingly backing away from the “fat is bad for you” mantra that dominated 20th century ideas about nutrition (see this Harvard University information page).
What kinds of fat should you eat? You can include almost as much monounsaturated fat in your diet as you choose; the premium example of this is extra virgin olive oil (“evoo”). The monounsaturated fats have been shown to promote cardiovascular health and to positively impact cholesterol balance. You should avoid highly refined industrially produced “vegetable” oils; stick to quality, preferably organic, cold-processed and expeller pressed oils. You may not realize that the saturated fats in Avocados, Coconuts, and other vegetable sources are widely embraced as healthy additions to your diet. And, because most of us don’t get nearly enough of them in our diets, you should probably start supplementing your diet with Omega-3 fatty acids, especially the fish oils DHA and EPA.
On the other hand, there ARE bad fats. You should certainly avoid “Trans-Fatty Acids” and “Hydrogenated Oils” (but you knew that already). And in general, you should avoid the most fatty cuts and parts of meat. It is also wise not to eat too many egg yolks. The reason for avoiding meat fats and eggs is not so much the “saturated fat,” or the “cholesterol” in these sources, but the highly inflammatory Omega-6 polyunsaturated fatty acid known as “arachidonic acid”. Of course, there’s good and bad in everything; some websites even promote arachidonic acid as a bodybuilding supplement. (But if you want to know more about the serious concerns about inflammation, arachidonic acid and other Omega-6 fatty acids, read Barry Sears’ book Toxic Fat; see the links page).
So, how much fat should you eat? It depends. You should eat enough protein and carbohydrates to supply your body’s needs, and then you should, along with this, eat that amount of fat that lets you maintain athletic performance and reach or maintain your desired body composition.
It should be pointed out that if you want to lose weight, the canonical Zone diet system recommends that people should eat about 1g of fat for every 3g of carbohydrates. So if you are eating 150g of CHO per day you would eat 50g of fat per day. To put that in perspective, if you ate no other source of fat (such as meat), you would add about 10 tsp. of olive oil to your food. On the other hand many CrossFitters and Zone diet system gurus recommend that active people and athletes should basically double, or even triple that amount of fat.