Weight Loss

 

Principal Proposed Treatments for Weight Loss  <Back to Top>

 

Chromium: May Help in Fat Loss Chromium is a mineral the body needs in only small amounts, but it's important to human nutrition. Although it has principally been studied for improving blood sugar control in people with diabetes, recent evidence suggests that chromium may also help reduce body fat, probably through its effects on insulin.5,6,7 A 3-month double-blind study of 122 moderately overweight people found that 400 mcg of chromium daily resulted in an average loss of 6.2 pounds of body fat, as opposed to 3.4 pounds in the placebo group. There was no loss of lean body mass.8 These results suggest that chromium can help you lose fat without losing muscle. However, six smaller double-blind placebo-controlled studies found chromium picolinate supplements produced no weight loss or change in lean body mass.9–14 These conflicting results may be due to differences in study size, the dosage of chromium, and the individuals enrolled. Overall, chromium does appear to be promising. Dosage The U.S. government recommendations for chromium are as follows: Infants 0 to 6 months, 10 to 40 mcg Infants 7 to 12 months, 20 to 60 mcg Children 1 to 3 years, 20 to 80 mcg Children 4 to 6 years, 30 to 120 mcg Adults (and children 7 years and older), 50 to 200 mcg The dosage of chromium used in weight-loss studies ranged somewhat higher than these guidelines, up to 200 to 400 mcg daily. There may be risks in taking excessive doses of chromium (see Safety Issues). Safety Issues At recommended doses, chromium is safe. However, chromium is a heavy metal that might conceivably build up and cause problems if taken to excess. There have been a few reports of kidney damage in people who took a relatively high dosage of chromium: 1,200 mcg or more daily for several months.15,16 There has been one report of a severe skin reaction caused by a form of chromium called chromium picolinate.17 Concerns have also been raised over the use of this substance in individuals suffering from depression, bipolar disease, or psychosis, because picolinic acids can change neurotransmitter levels.18 There are additional concerns, still fairly theoretical, that chromium picolinate could have adverse effects on DNA.19 If you have diabetes you should consult a physician before trying chromium, you may need to have your diabetes medication adjusted.20 The maximum safe dosages of chromium for nursing women or people with severe liver or kidney disease have not been established. Fiber: May Decrease Appetite Dietary fiber is important to many intestinal tract functions including digestion and waste excretion. It also removes bile acids from the gut, and thus has a mild cholesterol-lowering effect. An increasing number of studies suggest that fiber may also help people lose weight. It's thought to work by decreasing appetite—it bulks up in the stomach and causes a full feeling. Dietary fiber is primarily derived from the cell walls of plants. Whole, unprocessed grains, legumes, fruits, and vegetables all contain considerable proportions of fiber. There are two kinds: soluble fiber, which swells up and holds water, and insoluble fiber, which does not. Soluble fiber is found in psyllium, apples, and oat bran. Most other plant-based foods contain insoluble fiber. Fiber supplements may contain a variety of soluble or insoluble fibers from grain, citrus, vegetable, and even shellfish sources. What Is the Scientific Evidence for Fiber Supplements? Several small studies have evaluated fiber supplements for helping overweight people lose weight. For example, a double-blind placebo-controlled study found that among 97 mildly overweight women on a strict low-calorie diet, those who took 7 g of an insoluble fiber daily for 11 weeks lost 10.8 pounds compared to 7.3 pounds in the placebo group.21 However, a double-blind placebo-controlled study of 60 overweight children who were eating a normal, well-balanced diet found that 2 g each day of a fiber supplement had no effect on weight loss.22 One small study found that chitosan, an insoluble fiber derived from crustaceans, didn't reduce body weight.23  Preliminary evidence indicates that soluble guar fiber probably doesn't decrease appetite, whereas pectin fiber (from apples) may.24,25 Glucomannan, a source of dietary fiber from the tubers of Amorphophallus konjac, has also been tried for weight loss, but with mixed results.26–29 Dosage The typical dose of fiber used in such studies is 5 to 7 g per day. Safety Issues Fiber is essentially a food, and aside from a few reports of gastrointestinal discomfort, there are rarely any side effects associated with taking fiber supplements.

 

Other Proposed Treatments for Weight Loss  <Back to Top>

 

Pyruvate: Preliminary Evidence Is Encouraging Pyruvate is a natural compound that plays important roles in the body's manufacture and use of energy. It's not an essential nutrient, since your body makes all it needs. Evidence from a few small placebo-controlled studies suggests that pyruvate supplements may enhance weight loss.30,31,32  Unfortunately, these studies were all too small for the results to be taken as fully reliable. Although most products on the market contain only (or almost only) pyruvate, some also contain small amounts of a related compound, dihydroxyacetone, which the body converts to pyruvate. The combination of the two products is known as DHAP. Both pyruvate and dihydroxyacetone appear to be quite safe, aside from mild side effects such as occasional stomach upset and diarrhea. However, maximum safe dosages for children, women who are pregnant or nursing, or people with liver or kidney disease have not been established. A typical therapeutic dosage of pyruvate is 30 g daily. Keep in mind that even a small percentage of contaminant in such an enormous dose could be harmful, so be sure to use a quality product. 5-HTP: A Promising Option 5-Hydroxytryptophan (5-HTP) is a naturally occurring substance that your body manufactures on its way to making the brain chemical serotonin. Although it's primarily been studied as a possible antidepressant, preliminary evidence from three small double-blind placebo-controlled clinical trials suggests that 5-HTP may also help people lose weight.33,34,35 It's thought to work by raising levels of serotonin, which in turn may influence eating behavior. A typical therapeutic dosage of 5-HTP is 100 to 300 mg 3 times daily. No significant adverse effects have been reported in clinical trials of 5-HTP. Side effects appear to be limited to occasional mild digestive distress and possible allergic reactions. However, an alarming report raised safety concerns about 5-HTP in 1998, when the U.S. Food and Drug Administration reported detecting a chemical compound known as "peak X" in some 5-HTP products. Peak X has a frightening history involving tryptophan, which is an amino acid related to 5-HTP. Until about 10 years ago, tryptophan was widely used as a sleep aid, but it was taken off the market when thousands of people using it developed a disabling and sometimes fatal blood disorder; the same contaminant, peak X, was found to be associated with that disaster. Because the body turns tryptophan into 5-HTP, 5-HTP has been marketed as a safe replacement for the banned amino acid. It was assumed that 5-HTP could not possibly present the same contaminant risk as tryptophan because it is manufactured completely differently. However, the recent discovery that peak X exists in batches of 5-HTP is worrisome. Another safety issue with 5-HTP involves its interaction with carbidopa, a medication used for Parkinson's disease. Several reports suggest that the combination can create skin changes similar to those that occur in the disease scleroderma.36,37,38 In addition, 5-HTP should not be combined with drugs that raise serotonin levels, such as SSRIs (e.g., Prozac), other antidepressants, or the pain medication tramadol. There is a chance you might raise serotonin levels too high, causing a dangerous condition called serotonin syndrome. Safety in young children, pregnant or nursing women, and people with liver or kidney disease has not been established (although, in some studies children have been given 5-HTP without any apparent harmful effects). Calcium and Vitamin D Supplements Rapid weight loss in overweight postmenopausal women appears to accelerate osteoporosis slightly.39 For this reason, taking calcium and vitamin D supplements—always a good idea—may be especially appropriate here. Garcinia Cambogia: No Evidence That It Works Hydroxycitric acid (HCA), a derivative of citric acid, is found primarily in a small, sweet, purple fruit called Garcinia Cambogia, the Malabar tamarind. In animal studies, HCA suppressed appetite and thereby encouraged weight loss.40–44 It has also been suggested that HCA interferes with the body's ability to produce and store fat.45–48 However, the largest and best-designed human trial found no benefit with HCA,49 and another small placebo-controlled human study found HCA had no effect on metabolism.50 Caffeine and Ephedra: May Be Effective, but Not Recommended Caffeine and ephedra (also known as ma huang) are central nervous system stimulants that, when combined, may help people lose weight. Several well-designed studies examining the effect of a caffeine-ephedra combination indicate that it does promote weight loss.51–54 However, these stimulants affect the heart, and should be used only under physician supervision. Vitamin C: For Weight Loss, Too? Vitamin C, the single most popular vitamin supplement in the United States, has been tested in hundreds of clinical studies for dozens of illnesses from cancer to colds, and even for weight loss. Results of two small double-blind placebo-controlled studies suggest that extremely overweight people who take vitamin C supplements may lose some weight,55,56 but larger studies will have to be conducted before these results can be taken as recommendations. Conjugated Linoleic Acid (CLA) Conjugated linoleic acid (CLA) is a mixture of different isomers, or chemical forms, of linoleic acid. This is an essential fatty acid—a type of fat that your body needs as much as it needs vitamins. CLA has been proposed as a fat-burning substance, but the evidence that it works is mixed.57–60 Evening Primrose Oil: Questionable Benefit Evening primrose is a native American wildflower, named for the late afternoon opening of its delicate flowers. Its seeds are one of the best natural sources of cis-gamma-linolenic acid (GLA), an important member of the essential omega-6 family of fatty acids. One double-blind study of 74 women found that evening primrose oil failed to produce any weight loss as compared to placebo; however, another investigation that restricted treatment to 47 people with a family history of obesity found it produced a small but significant weight loss.61,62 Other Treatments Preliminary evidence suggests that a special type of fat known as diacylglycerol may help individuals lose fat, especially fat around the abdomen.63 One double-blind placebo-controlled trial investigated the possible weight loss effects of spirulina.64 However, while individuals taking 8.4 g of spirulina daily lost weight, the difference between the spirulina group and the placebo group was not statistically significant. Larger and longer studies are needed to establish whether spirulina is indeed an effective treatment for obesity. Other treatments often recommended for weight loss, but with little scientific backing, include pantothenic acid, zinc, and coenzyme Q10. One small double-blind trial found the supplement L-carnitine ineffective for weight loss.65 What About High-Protein Diets? High-protein, low-carbohydrate diets have some interesting scientific evidence behind them, but they have not yet been proven to work as claimed. However, contrary to some reports, they haven't been proven dangerous either. According to advocates, a high-protein, low-carb diet can help you achieve your ideal weight, prevent heart disease, control diabetes, and prolong life. However, conventional medical authorities are skeptical, pointing to studies that show a diet centered around whole grains reduces the risk of heart disease and will probably help you live longer. Because the high-protein, low-carb diet is the opposite of that, doctors are concerned that it isn't healthy for you. However, advocates of high-protein diets claim that their approach is even healthier than the whole-grain centered diet. Intriguing evidence suggests that there could be some truth to this idea. What Is the Scientific Evidence for High-Protein Diets? The rationale for the high-protein diet involves insulin. When you eat carbohydrates, the body releases insulin to process the sugars they contain. There is some reason to believe that the less insulin your body produces, the healthier you will be (within limits), and the easier it will be to lose weight. Insulin release helps fat cells create fat. In addition, elevated insulin levels tend to lead to an increased risk of heart disease. One large study found that increased insulin levels were twice as strong a predictor of future heart disease as elevated cholesterol.66 A high-protein, low-carb diet tends to reduce insulin levels, and could therefore help prevent heart disease. A large study lends support to this concept. It examined the relationship between protein intake and heart disease in 80,082 women during a 14-year period.67 The results suggest that a diet replacing carbohydrates with protein does not increase heart disease risk and might even reduce it. In addition, high intake of refined carbohydrates (such as sugar and white flour) has been found to be a significant risk factor for heart disease.68 But does the high-protein diet help you lose weight? The answer is: Maybe. The research reported so far is intriguing, but not definitive. Studies currently in progress should settle the issue in the next several years. Safety Issues If you have kidney problems, eating a high-protein diet could be dangerous. High-protein intake also reduces the effectiveness of medication for Parkinson's disease. Also, don't get too extreme and eliminate your entire carbohydrate intake: this will alter your metabolism in an unhealthy way. Finally, choose healthy protein sources such as fish, legumes, and lean meat.

References  <Back to Top>

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