VITAMINS & MINERALS
How Do I Pick a Diet That Fits My Lifestyle?
Diet, exercise, and supplements help battle the bulge
Get the skinny on weight loss. Discover what works for you to improve your chances of losing weight and keeping it off. According to research or other evidence, the following self-care steps may be helpful:
About weight loss and obesity
For overweight women, weight loss can significantly improve physical health. A four-year study of over 40,000 women found that weight loss in overweight women was associated with improved physical function and vitality as well as decreased bodily pain. The risk of death from all causes, cardiovascular disease, cancer, or other diseases increases in overweight men and women in all age groups. Losing weight and keeping it off is, unfortunately, very difficult for most people. However, repeated weight loss followed by weight regain may be unhealthy, as it has been associated with increased heart disease risk factors and bone loss in some studies. Rather than focusing on weight loss as the most important health outcome of a change in diet or lifestyle, some doctors advocate paying more attention to overall fitness and reduction in known risk factors for heart disease and other health hazards.
Dietary changes that may be helpful
Low-fat, low-calorie, high-fiber, balanced diets are recommended by many doctors for weight loss. According to controlled studies, when people are allowed to eat as much food as they desire on a low-fat diet, they tend to lose more weight than people eating a regular diet. However, low-fat diets have not been shown to be more effective than other weight-loss diets that restrict calories. Nonetheless, a low-fat, high-fiber, balanced diet has additional potential benefits, such as reducing the risk of chronic diseases including heart disease and cancer.
Preliminary research indicates that people who successfully lost weight got less of their total calories from fat and more of them from protein foods. They also ate fewer snacks of low nutritional quality and got more of their calories from “hot meals of good quality.” Other preliminary studies find that dieters who maintain long-term weight loss report using fat restriction and eating a regular breakfast as key strategies in their success.
Low-carbohydrate, high-protein diets
The effect of low-carbohydrate diets on cardiovascular risk is also an unresolved issue. The short-term studies discussed above found that blood cholesterol levels did not worsen with these diets. Other heart-disease risk factors (triglyceride levels and insulin sensitivity) actually improved with a low-carbohydrate diet. Some studies, however, have shown a worsening of certain cardiovascular risk factors in people using a low-carbohydrate, high-fat diet for up to one year. Adverse changes included increases in blood levels of homocysteine, lipoprotein(a), and fibrinogen, and a decrease in blood flow to the heart. Individuals wishing to consume a very-low-carbohydrate diet for weight loss or for other reasons should be monitored by a doctor.
Some research has investigated weight-loss diets that are high in protein, but moderate in fat and not as low in carbohydrate content as the diets discussed above. While this type of diet does not usually lead to greater weight loss than other diets when calorie intakes are kept equal, one controlled trial found greater body fat loss in women eating a diet almost equal in calories and fat but approximately twice as high in protein and lower in carbohydrate compared with a control group’s diet. Another controlled trial compared two diets similar in fat content but different in protein and carbohydrate content. People allowed to eat freely from the higher protein diet (25% of calories from protein, 45% calories from carbohydrate) consumed fewer calories and lost more weight compared with people eating the lower protein diet (12% of calories from protein, 59% calories from carbohydrate).
Lifestyle changes that may be helpful
Exercise appears to help people maintain weight loss. People who have successfully maintained weight loss for over two years report continuing high levels of physical activity. Combining exercise with healthier eating habits results in the best short- and long-term effects on weight loss, and should reduce the risk of many serious diseases.
Vitamins that may be helpful
Pyruvate, a compound that occurs naturally in the body, might aid weight-loss efforts. A controlled trial found that pyruvate supplements (22 to 44 grams per day) enhanced weight loss and resulted in a greater reduction of body fat in overweight adults consuming a low-fat diet. Three controlled trials combining 6 to 10 grams per day of pyruvate with an exercise program reported greater effects on weight loss and body fat than that seen with a placebo plus the exercise program.
5-HTP (5-hydroxytryptophan), the precursor to the chemical messenger (neurotransmitter) serotonin, has been shown in three short-term controlled trials to reduce appetite and to promote weight loss. In one of these trials (a 12-week double-blind trial), overweight women who took 600 to 900 mg of 5-HTP per day lost significantly more weight than did women who received a placebo. In a double-blind trial with no dietary restrictions, obese people with type 2 (non-insulin-dependent) diabetes who took 750 mg per day of 5-HTP for two weeks significantly reduced their carbohydrate and fat intake. Average weight loss in two weeks was 4.6 pounds, compared with 0.2 pounds in the placebo group.
The ability of 7-KETO (3-acetyl-7-oxo-dehydroepiandrosterone), a substance related to DHEA, to promote weight loss in overweight people has been investigated in one double-blind trial. Participants were advised to exercise three times per week for 45 minutes and to eat an 1,800-calorie-per-day diet. Each person was given either a placebo or 100 mg of 7-KETO twice daily. After eight weeks, those receiving 7-KETO had lost more weight and lowered their percentage of body fat further compared to those taking a placebo. These results may have been due to increases in levels of a thyroid hormone (T3) that plays a major role in determining a person’s metabolic rate, although the levels of T3 did not exceed the normal range.
In a study of obese people consuming a low-calorie diet for 24 weeks, those receiving a calcium supplement (800 mg per day) lost significantly more weight than those given a placebo. Calcium was effective when provided either as a supplement, or in the form of dairy products. In a second study, however, the amount of weight loss resulting from calcium supplementation (1,000 mg per day) was small and not statistically significant. In that study, participants' typical diet contained more calcium than in the study in which calcium supplementation was more effective. Thus, it is possible that calcium supplementation enhances weight loss only when the diet is low in calcium.
A double-blind trial found that exercising individuals taking 1,800 mg per day of conjugated linoleic acid (CLA) lost more body fat after 12 weeks than did a similar group taking a placebo. However, two other studies found that amounts of CLA from 0.7 to 3.0 grams per day did not affect body composition. Most double-blind trials have found that larger amounts of CLA, 3.2 to 4.2 grams per day, do reduce body fat; however, one double-blind study of experienced strength-training athletes reported no effect of 6 grams per day of CLA on body fat, muscle mass, or strength improvement.
Fiber supplements are one way to add fiber to a weight-loss diet. Several trials have shown that supplementation with fiber from a variety of sources accelerated weight loss in people who were following a low-calorie diet. Other researchers found, however, that fiber supplements had no effect on body weight, even though it resulted in a reduction in food intake.
Supplementation with 3 to 4 grams per day of a bulking agent called glucomannan, with or without a low-calorie diet, has promoted weight loss in overweight adults, while 2 to 3 grams per day was effective in a group of obese adolescents in another controlled trial.
Herbs that may be helpful
Green tea extract rich in polyphenols (epigallocatechin gallate, or EGCG) may support a weight-loss program by increasing energy expenditure or by inhibiting the digestion of fat in the intestine. Healthy young men who took two green tea capsules (containing a total of 50 mg of caffeine and 90 mg of EGCG) three times a day had a significantly greater energy expenditure and fat oxidation than those who took caffeine alone or placebo. In a preliminary study of moderately obese individuals, administration of a specific green tea extract (AR25) resulted in a 4.6% reduction in average body weight after 12 weeks. The amount of green tea extract used in this study supplied daily 270 mg of EGCG and 150 mg of caffeine. While caffeine is known to stimulate metabolism, it appears that other substances besides caffeine were responsible for at least part of the weight loss. Although the extract produced few side effects, one individual developed abnormal liver function tests during the study. Additional studies are needed to confirm the safety and effectiveness of green tea extracts for promoting weight loss.
One small, double-blind clinical study in humans found that hoodia latex and inner plant can significantly reduce food intake. Available products are of unknown quality and much more work remains to be done to determine if hoodia will be a sustainable, safe way to reduce appetite.
Copyright © 2008 Healthnotes, Inc. All rights reserved. Republicationor redistribution of the Healthnotes® content is expressly prohibitedwithout the prior written consent of Healthnotes, Inc. Healthnotes Newsletteris for educational or informational purposes only, and is not intendedto diagnose or provide treatment for any condition. If you have anyconcerns about your own health, you should always consult with ahealthcare professional. Healthnotes, Inc. shall not be liable for anyerrors or delays in the content, or for any actions taken in reliancethereon. HEALTHNOTES is a registered trademark of Healthnotes, Inc.