What is your opinion of the Zone diet promoted by Dr. Barry Sears?


What is your opinion of the Zone Diet promoted by Dr. Barry Sears? Although it does restrict carbohydrates, it prescribes them at 1.33 times the grams of protein so I don’t think it is in the same category as the low carbohydrate diets. In other words, it is not at all ketogenic. In addition, the carbohydrates to be emphasized are those having a low to moderate glycemic index.

The protein requirement is calculated from a consideration of a person’s lean body mass (LBM) and level of activity. So for example, since I have an LBM of 133 pounds and am moderately active, my protein requirement is about 90 grams/day. Sears shows in his book that using the same calculations a “typical” (and mostly sedentary) American male (23% body fat and 154 pounds) would require only 60 grams/day, as is usually recommended for everyone.

Initially, the fat intake on this diet (emphasizing monounsaturated) is calorically equal to the protein intake. Later, one increases monounsaturated fat in order to maintain weight (this part is probably controversial).

I have concluded that my calorie intake is somewhat lower overall than it was before – more like 1800 calories/day as opposed to 2600 calories/per day before though my weight seems to be holding steady now.

I was drawn to this diet due to high triglycerides (which were made worse on a low fat/high carbohydrate diet).

I have lost about 8 pounds, which my gym confirms was entirely fat, as my LBM has stayed the same. I feel more energetic and have more exercise capacity as well.

Do you have any concerns about this diet?

I am familiar with the Zone diet, however, am responding based on your interpretation of this diet.

In your Zone calculations, your protein component is about 1 1/2 times higher than your RDA (Recommended Dietary Allowance) of 63 grams per day. Ninety grams of protein in an 1800 calorie diet equates to 360 calories or 20% of calories from protein which is within recommended guidelines. If you calculate your protein requirement from your present lean body mass (muscle), then you would not have additional protein to build more muscle through weightlifting. Have you thought about this concept of how to fuel building more muscle if that is your goal?

I am not sure how you calculated your fat component being calorically equal to protein since meat (protein) has fat ranging from 3.5 grams (lean) to 7 grams (fatty steak) of fat per ounce. Also, protein has only 4 calories per gram compared to fat’s 9 calories per gram. Therefore, 90 grams of protein times 4 calories per gram is 360 protein calories. Then 360 protein calories divided by 9 fat calories per gram = 40 grams of fat as your goal.

If you divide 90 grams of protein by 7 grams protein per ounce of meat that equals almost 13 ounces of meat. Then 13 ounces of meat times a minimum of 3.5 fat grams per ounce lean meat = 45 grams of fat or 5 excess grams of fat you are allotted.

Monounsaturates are the best healthy oils and do not increase blood cholesterol levels. By increasing your protein intake to 90 grams, you invariably will increase your consumption of saturated fats from meat unless your proteins are entirely from vegetable sources which will add carbohydrates not found in meat. How have you accounted for the fat in meat and still add monounsaturated oils like olive, peanut, avocados, etc. in order to stay within this diet’s guidelines?

Elevated triglycerides are treated with a moderate carbohydrate, no sugar, and no alcohol, moderate fat nutrition therapy. Not a low-fat nutrition therapy without any other restrictions.  While triglycerides are a fat and what body fat is composed of, it can be lowered in the blood by limiting sugar and alcohol. Low carbohydrate diets should decrease triglycerides, which should measure below 150 milligrams/deciliter. Triglycerides comprise all the VLDL (very low-density lipoprotein) bad component of blood fats.

Your carbohydrate is 120 grams (90 grams times 1.33) in an 1800 calorie diet and equals only 27% carbohydrates. This is below the minimum 130 grams of carbohydrate recommended for anyone, even for a nutrition therapy to lower triglycerides. Carbohydrates that produce a low to moderate glycemic index (how much does a food increases in blood sugar) are recommended to lower triglycerides. Around 45% of calories from carbohydrates would be better.

I believe that your calculations may be off if you eat 90 grams of protein (360 calories), 40 fat grams (360 protein calories / 9 fat calories per gram) and 120 grams of carbohydrate (1.33 times 90 grams protein) then 120 times 4 carbohydrate calories per gram is 480 calories. Therefore protein 360 calories, fat 360 calories, and 480 carbohydrate calories equal only 1200 calories, not 1800 calories. If you have underestimated any of these 3 calorie sources in your diet and are eating 1800 calories per day, then one of your calculations is off. Otherwise, you have overestimated how many calories per day you eat and are eating far less. Anyway, recheck your calorie math using the figures I have provided.

Try my Healthy Body Calculator® to calculate your Calorie Goal and grams for protein, fat, carbohydrate. No math required.

As to your lean body mass, I wonder what method was used to assess it? If your gym used calipers or electrical impedance, both can produce erroneous readings depending on the client’s hydration status, fasted state before eating food for the day, and the skill of the person performing the test. I used skinfold calipers on hospitalized patients and it takes some skill development to achieve the accuracy of underwater weighing used in exercise science which is the most accurate if performed correctly.