What is a balanced diet?

What is the Best Balanced Diet?

It is easy to say that you should eat a balanced diet. But what balance is best? Is the 40% carb/30% protein/30% fat ratio of the Zone diet best?(1) Or the 40 protein/40 fat/20 carb ratio of the Atkins program?(2) Or the 60 carb/20 protein/10 fat of the Pritikin/Dean Ornish approach?(3,4,5,6) How much of what type of food should be consumed on a daily basis? Or should we be focused on the type or quality of carbohydrate, protein, and fat? How much carbohydrate/protein/fat is considered high or low?

There is research that has supported some of the benefits of each of the approaches mentioned above. And a percentage of people who follow each of these programs have reached their weight loss goals. But I believe that a thorough reading of the published nutrition research points to a low glycemic carbohydrate/lean protein/omega 3 fat dietary approach as the best overall balance, which is what we recommend in our First Line Therapy nutrition program.

The higher protein/lower carbohydrate program, like the Zone or Atkins, has some benefits in that they promote a lower glycemic response and lower insulin levels, thus improving insulin insensitivity. But followers of these regimens typically end up with less energy and decreased performance due to inadequate carbohydrates for energy. If you follow the very low carbohydrate Atkins diet, you will be eating lots of saturated fats and this will raise your cardiovascular disease risk. And you will be missing out on some of the health promoting phytonutrients that are contained in fruits, vegetable, legumes, and whole grains that you are only eating very limited amounts of.

And by focusing too much on the amount of macronutrients, you lose the importance of the type of carbohydrate, and this may be more important than just the total amount. For one thing, the glycemic index of the carbohydrates you eat will drastically change the effect they have on your health. Eating high glycemic carbohydrates will raise your blood sugar and insulin levels and increase your risk of diabetes and cardiovascular disease. Eating low glycemic carbohydrates will improve your glucose control and lower your insulin levels closer to an optimal level and reduce your risk of diabetes and cardiovascular disease. (The glycemic index is a measure of how rapidly ingested foods are turned into sugar in your body.)(12)

Another important factor is that you eat carbohydrates that are higher in fiber, which slows the breakdown into blood sugar. Fiber intake reduces the risk of cancer through a number of mechanisms, including altering the exposure of the colonic mucosa (lining of the colon) to carcinogens.(7,8) Fiber increases stool size and dilutes the concentration of carcinogens that may be present. Fiber also has a positive effect on hormone balance by decreasing reabsorption of steroid molecules through the intestines. A higher fiber diet may be protective against various types of cancer, including colon and breast cancer.(9) The National Cancer Institute recommends 20-35 grams of fiber per day.

It is also important not only how much fat you consume, but what type of fat. You need to try to consume healthy fats, including monounsaturated fats, (such as olive and canola oils, nuts, seeds, nut butters, and avocados) and fats that are high in omega 3 fatty acids, (such as fish oil and flax seeds). Adequate fat intake is necessary for hormone production, nervous system function, and other important physiological processes. However, animal (saturated) fats, polyunsaturated fats (coconut, palm kernal, corn, and safflower oils), and hydrogenated fats or trans fats (such as found in most margarines) are unhealthy and should be avoided.(10,11) These types of fats are pro-inflammatory, raise your cholesterol levels, and increase your risk of cardiovascular disease and various types of cancer.

RESEARCH:

1. Sears B, Lawren B. Enter The Zone. New York: Harper Collins Publishers, 1995.
2. Holt SH, Brand-Miller JC, Petocz P. An insulin index of foods: the insulin demand generated by 1000-kJ portions of common foods. Am J Clin Nutr. 1997; 66(5):1264-1276.
3. Ornish D, Brown SE, Scherwitz LW, et al. Can lifestyle changes reverse coronary heart disease? The Lancet. 1990; 336: 129-133.
4. Ornish D, Scherwitz LW, Billings JH, et al. Intensive lifestyle changes for the reversal of coronary heart disease. JAMA. 1998; 280(23): 20-91.
5. Jamison J. Nutritional prevention of cancer: current status, future possibilities. Top Clin Chiro. 1999; 6:45-53.
6. Costill DL, Hargreaves M. Carbohydrate nutrition and fatigue. Sports Med. 1992; 13(2):86.
7. Weisburger JH, Reddy BS, Rose DP, et al. Protective mechanisms of dietary fibers in nutritional carcinogensis. In: Bronzetti G, et al, eds. Antimutagenesis and Anticarcinogenesis Mechanisms III. New York: Plenium Press; 1999:45-63.
8. Alabaster O, Tang Z, Shivapurkar N. Dietary fiber and the chemopreventive modulation of colon carcinogenesis. Mutat. Res. 1996; 350:185-197.
9. Jamison,ibid.
10. Willett, WC, et al. Intake of trans fatty acids and risk of coronary heart disease among women. Lancet. 1993; 341: 581-585.
11. Murray M. Encyclopedia of Nutritional Supplements. Rocklin, CA: Prima Health; 1996. Ch 32: Understanding Fats and oils. 237-248.
12. Foster-Powell K, Holt SHA, Brand-Miller JC. International table of glycemic index and glycemic values: 2002. Am J Clin Nutr. 2002; 76:5-56.