Ask a Dietitian

As seen on BCTV November 21/00

No matter what diet you follow, if there is a caloric deficiency, i.e. if you eat fewer calories than you burn, you will lose weight. Whether the calories are from carbohydrates, proteins or fat has little or no effect on how well the calories are used by the body. If followed correctly, people will lose weight on The Zone by Barry Sears, The New Diet Revolution by Dr. Atkins, Sugar-Busters and Dean Ornish’s Eat More, Weigh Less. How? They all do it the same way-they cut calories. The problem isn’t weight loss, it is weight maintenance and the risks that accompany some of these diets.

There is some evidence that people who ate a higher protein diet (25% of calories) and lower carbohydrates (45%) and moderate fat (30%) ate less food than the high carbohydrate, low protein diet and hence lost more weight. It is thought that protein foods have a higher satiety value so people feel more full after eating them and therefore consumed fewer calories. People in the high carbohydrate group tended to eat more sweets and total calories and therefore lost less weight. However, as the percentage of protein or fat increases, so do the health risks.

The health risks with a high fat (55%) diet (Atkins’s New Diet Revolution), particularly saturated fat (18%) from animals are well known. There may be a rise in LDL (bad) cholesterol or a slight reduction if there is sufficient weight loss. There is also an increased risk for developing colon and prostate cancers. The low carbohydrate content will force your body to use fat as fuel and put you into ketosis. Some of the negative side effects of this are a reduction in energy level, bad breath from the ketones in your blood and constipation due to a lack of fibre from healthy foods such as fruits and whole grains. Moreover, the Atkins’s diet runs short on some nutrients. To be safe, all “Zone dieters” should take a multivitamin and mineral supplement as well as calcium.

What about very high protein (30%), moderate fat (30%) and low carbohydrate (40%) diets such as the Zone? There is some evidence that shows a high protein diet is taxing on the kidneys, which can worsen already existing kidney disease and may set the stage for future kidney disease. Moreover, these diets are dehydrating. Within the first week on a high protein diet you can lose a lot of weight, depending on your body fat percentage. Unfortunately, most of the loss is water. A mere 2-5 pound water weight loss can reduce your energy level significantly and can hinder your exercise performance. High protein intakes have also been shown to increase urinary losses of calcium, which can lead to osteoporosis long term. To follow the Zone diet precisely, the protein sources should be from low fat foods such as egg whites, low fat cottage cheese, chicken and fish. This may be a challenge for some. Moreover, the calories are very low, 1000 kcal/day. For an active individual this is likely impossible. The low carbohydrate intake usually results in a low fibre intake as well which can lead to constipation and diverticulosis. The worst part for these dieter is that the minute they go off the high protein diet and begin to eat carbohydrate again the weight is usually all regained.

The Bottom Line:
Variety, balance, moderation and hydration. It seems boring but you need to think long-term. What can you see yourself doing forever? Eating a variety of foods from all the food groups, emphasizing vegetables and fruits, choosing whole grain products, lower fat dairy products and leaner meat and the alternatives more often is the healthiest approach to weight loss. Be sure to use the good oils such as olive and canola oil, limit your intake of high fat and high sugar processed foods. Don’t eliminate the foods you love, just reduce your intake of them. Stay well hydrated and most of all enjoy your food. Food should be pleasurable.

Watch for the Eating for Energy segment every Tuesday on BCTV’s Noon News Hour!