Health Options
Best diets avoid extremes
in carb, fat, protein intake
The ongoing nationwide obsession with finding the best diet is reminiscent of Goldilocks' search for the porridge that was "just right." As we pointed out in the last two Health Options columns, the best diet for most of us is unlikely to be at one extreme or another.Question: What makes a diet extreme?
Answer: When one or more components of the diet become greater than or less than what is compatible with short- or long-term health.
Q: Are low-carbohydrate diets extreme?
A: Yes. Although there is some rationale for therapeutic use of low-carbohydrate diets in treating specific health conditions, these diets can be harmful to the average person.
When a diet restricts high-carbohydrate foods, most calories must come from protein and fat. The most popular such diet, promoted by Dr. Robert Atkins, restricts carbohydrate intake to no more than 80 calories per day for the first two weeks. After that, the diet allows for an increase in carbohydrate to an average of about 250 calories per day for maintenance of the weight loss.
Consequently, if a person needs 2,000 calories to maintain his or her weight, 1,750 calories must come from a combination of protein and fat. Suppose a dieter gets half of these calories from protein and half from fat. For a 150-pound person, that would be equal to four times the Recommended Daily Allowance, or RDA, for protein and almost twice the recommended intake of fat.
If our dieter lowers the fat, the protein goes up. But it's already way too high. Lowering the protein results in a rise in fat, but that amount is already too high for cardiovascular health. In other words, "you can't get there from here."
Q: At what point is protein intake considered excessive?
A: An exact cut-off point is debatable and depends on other components of a person's diet and exercise habits. As a rough rule of thumb, twice the RDA is a reasonable upper limit for healthy protein intake. Twice the protein RDA equals about three-fourths of a gram of protein per day for each pound of body weight (about 110 grams of protein per day for a 150 pound person).
Q: My wife loves the Atkins diet and is not going to change. How can she minimize the potential health problems the diet can cause?
A: Encourage her to include plenty of milk products and fish as her protein sources. This will help to balance the increased loss of urinary calcium caused by excess protein and provide more omega-3 fatty acids to reduce the cardiovascular disease risks inherent in most high-fat diets.
Also, drink plenty of water. These adjustments do not make a bad diet good -- only less damaging.
Q: Can a low-fat/high-carbohydrate diet be too extreme?
A: Yes. At the extremes, these diets can be too low in essential fatty acids, resulting in problems with blood pressure regulation, among other things. As people adapt to low-fat/high-carb diets, some tend to eat too many calories and regain the weight they initially lost. At the same time, for less active people with low calorie needs, the diet can provide too little protein to maintain or build muscle. The end result is decreased calorie needs and, again, weight gain.
Like Goldilocks, most of us would find more benefit in a good nap followed by a workout (minus the stress of running from bears) and less obsession with dietary extremes.
Health Events
Alan Titchenal, Ph.D., C.N.S., is a sports nutritionist in the
Department of Human Nutrition, Food and Animal Science,
University of Hawaii-Manoa.Joannie Dobbs, Ph.D., C.N.S., is a food and nutrition consultant
and owner of Exploring New Concepts, a nutritional consulting firm.
She is also responsible for the nutritional analyses
indicated by an asterisk in this section.