Macronutrient ratios cannot be intelligently discussed without reference to both calories and food weights. Ratios are usually described in percentages of calories and weight in grams. Percentages will differ dramatically from weight since the caloric energy of fat is 9 calories per gram whereas the caloric energy of protein and carbohydrate is just 4 calories. That is why fat is such a good storage vehicle. It is more than twice as dense in energy as either protein or carbohydrate.
This is a big subject, so to include both macronutrient ratios and calories (as is necessary because they are dependent), it will be assumed for this discussion that all food ingested will be whole foods (no processed foods), and all foods will avoid, in Dr. Kurt Harris’s words, the Neolithic Agents of Disease (NAL): wheat, excess fructose, and excess linoleic acid (Omega 6s). Since I am long-time Type 2 diabetic, I will also attempt to avoid all starches (even so-called “safe” starches) and all sugars, even “natural” sugars that are found in fruits and certain vegetables such as beets, peas, corn and carrots.
For a baseline reference, I will use the Standard American Diet (SAD) conveniently found on the HHS/USDA’s “Nutrition Facts” panel on processed food packaging. Macronutrient ratios are based on a 2000 calorie diet which is what women of a certain age need to maintain their weight. (A man is supposed to need 2200 calories.) The “% Daily Value” is based on the recommendation to eat 300 grams of carbohydrate a day. That’s 1200 calories (300 x 4) or 60% of 2000 calories. Surprised? The protein recommendation is 50 grams, which is 200 calories (50 x 4) or 10% of 2000 calories. The fat recommendation is 65 grams or 585 calories (65 x 9) which is <30% of 2000 calories. 1200 + 200 + 585 = 1985, say 2000.
I consider this reference standard to be very high carb, low protein, low-to-moderate fat. Although the government hasn’t revised the Nutrition Facts standards, they do appear in recent permutations of the “Dietary Recommendations for Americans” to be lowering the carb percentage a little (without explicitly saying so), but they also want you to lower your fat intake (at least saturated fat and cholesterol), and now refer to fat simply as oils, by which they explicitly mean vegetable oils (corn, soy bean, sunflower, safflower, Canola, etc.). It is these specific oils that I and like-minded thinkers are recommending be completely avoided due to instability(#21 here). My cooking oil preferences in fat are coconut oil, butter and ghee (and tallow and lard) – all saturated fats – and olive oil, a monounsaturated fat, for non-cooking use.
Another “reference standard” that may be closer to the currently recommended level of macronutrients that the government appears to advocate is represented by the contents of the Nestlé Nutrition product, Optifast. Their 510kcal (2.1MJ) serving contains 46.4% carbs, 32.5% protein and 20.1% fat. That is lower in both carbs and fat but much higher in protein than the SAD. As a further reference, in actual practice surveys show that American men eat 16%, and women 15%, of calories from protein. Most nutrition experts recommend no more than 30% of calories should come from protein, and then only when eaten with fat, and then only with blood tests that show no evidence of kidney disease.
What then are the other ranges of macronutrients? What, for example is considered low-carb? There is no definitive percentage but many people now consider 50 to 100 grams/day to be low-carb (vs. 300g in the SAD). Fifty grams is 200 calories or 10% of a 2000 calorie diet. 100g is 20%. That’s much better than 300g and a sure way to lose weight. Very low carb would be less than (<) 50g/day. Personally I eat about 15g/day but only 1200 calories total, so 15 x 4 = 60 calories which is only 5% of 1200. There is no minimum requirement for carbs, so some days I eat 5g with breakfast, zero at lunch, and 10 with dinner. If I skip dinner, I really lose weight. When I eat almost all fat and protein, I don’t get hungry.
That’s where calorie restriction comes into play. If you seriously restrict calories and eat a “balanced diet” of carbs, protein and fat, you WILL feel starved because your body IS being starved. You have limited the energy ingested and you have limited your body’s ability to access the stored fat on your body by eating carbs. Your body “notices” you have access to “quick energy” from readily available carbs (fruits and vegetables which seem to it to be “in season”), so it asks for (as in “craves”) more sugar. As long as you are a “sugar burner,” it “reasons,” you don’t need to access the dense fat reserves stored around your midriff. Insulin, the hormone secreted by your pancreas to transport glucose (the “sugar” broken down from all carbs) to your cells, is “telling” your fat cells to stay put and wait for the impending famine. Your body is doing you a big favor, it “thinks.” No matter how hard you try, it won’t let you burn your precious fat stores. You’re going to need it later, it says. It is going to protect you. It’s wants you to survive the winter that never comes….So, the only way you can restrict calories without hunger, if you want to do that to lose weight, is to restrict carbohydrates very severely. The number of grams and percentages of total calories will vary from person to person, due to differences in size and activity levels and hormonal issues (thyroid, or pregnancy, just for example). So will the number of days that it will take your body to get the message that the quick energy foods are no longer “available” – their season has passed – but when it does, it will use the fat it has safely put away for you. Your body is a beautifully designed machine, tuned to do just what you want it to do, if you ask it in a nice way. When you do, you are both happy.