Weight Loss and Obesity

About one-third of the U.S. population is overweight.1 One in five people not only exceeds ideal weight, but also meets the clinical criteria for obesity. In the 1990s, rates of obesity more than doubled, and are currently rising by over 5% per year.2 3 Because excess body weight is implicated as a risk factor for many different disorders, including heart disease, diabetes, several cancers (such as breast cancer in postmenopausal women, and cancers of the uterus, colon, and kidney), prostate enlargement (BPH), female infertility, uterine fibroids, and gallstones, maintaining a healthy body weight seems prudent. 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.4 The risk of death from all causes, cardiovascular disease, cancer, or other diseases increases in overweight men and women in all age groups.5 Losing weight and keeping it off is, unfortunately, very difficult for most people.

Being overweight is a risk factor for gestational diabetes, preeclampsia, gestational hypertension, and various other disorders of pregnancy.

Excess body mass has the one advantage of increasing bone mass—a protection against osteoporosis. Probably because of this, researchers have been able to show that people who successfully lose weight have greater loss of bone compared with those who do not lose weight.6 People who lose weight should, therefore, pay more attention to preventing osteoporosis.

Checklist for Weight Loss and Obesity

Rating Nutritional Supplements Herbs
3Stars Multivitamin-mineral (for very-low-calorie diets)
Pyruvate		  
2Stars 5-HTP
7-KETO
Fiber
Glucomannan		 Cayenne
Ephedra
1Star (-)-Hydroxycitric acid (HCA)
Chromium
DHEA
L-carnitine
Spirulina		 Coleus
Green tea
Guaraná
Guggul
Psyllium
3Stars Reliable and relatively consistent scientific data showing a substantial health benefit.
2Stars Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit.
1Star An herb is primarily supported by traditional use, or the herb or supplement has little scientific support and/or minimal health benefit.

How is it treated? Conventional treatment typically includes dietary changes to limit fat and calories, increased exercise, and changes in eating habits or patterns. Medications commonly prescribed for weight loss include stimulants (e.g., dextroamphetamine [Dexedrine®] and methamphetamine [Desoxyn®]), appetite suppressants (e.g., benzphetamine [Didrex®], dexfenfluramine [Redux®], fenfluramine [Pondimin®]), and fat absorption blockers (e.g., orlistat [Xenical®]). In severe cases, surgical options to reduce the size of the stomach or to bypass a portion of the stomach and intestines may be recommended.

Dietary changes that may be helpful: Societies in which people eat less fat tend to have lower rates of obesity. A low-fat diet is, however, no guarantee of normal body weight.7 Sixty percent of the South African population is overweight, despite a comparatively low fat intake (about 22% of calories from fat).8 Foods with a high proportion of calories from fat should be eliminated from the diet or limited; these include red meat, dark poultry meat, poultry skins, fried foods, butter, margarine, cheese, milk (except skim milk), junk foods, and most processed foods. Vegetable oils, nuts, seeds, and avocados should be consumed in moderation, although these foods are healthful for people without weight problems. The diet should instead be based on fruits, vegetables, whole grains, and nonfat dairy products (with low-fat fish for nonvegetarians).

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.”9

Adequate amounts of dietary fiber are believed to be important for people wishing to lose weight. Fiber contains bulk and tends to produce a sense of fullness, helping people consume fewer calories.10 There is conflicting research on the effect of fiber intake on weight loss, however. Some trials have shown that supplementation with a source of fiber accelerated weight loss in people who were following a low-calorie diet.11 12 In another trial, supplementation with a bulking agent called glucomannan (1.5 grams before breakfast and dinner) promoted weight loss in overweight people who were not following a special diet.13 Other researchers found, however, that increasing fiber intake had no effect on body weight, even though it resulted in a reduction in food intake.14 Different types of dietary fiber are available from a variety of sources, and the recommended amount depends on the type being used. People wishing to use a fiber supplement should consult with a doctor.

Although the relationship between food sensitivities and body weight remains uncertain, according to one researcher, chronic food allergy may lead to overeating and obesity.15

People who go on and off diets frequently complain that fewer calories result in weight gain with each weight fluctuation. Evidence now clearly demonstrates that the body gets “stingier” in its use of calories after each diet.16 This means it becomes easier to gain weight and harder to lose it the next time. Dietary changes need to be long term.

Foods containing high amounts of carbohydrate are sometimes measured on a scale called the Glycemic Index (GI). The GI is a numerical value assigned to a particular food based on that food’s ability to raise and sustain blood glucose levels, relative to the ability of a glucose beverage to do the same. Eating foods with a high GI (such as white rice, baked potato, corn flakes, white bread) promotes a more rapid return of hunger and increases subsequent intake of calories compared to eating similar foods with a lower GI (such as brown rice, all-bran cereal, oat bran bread).17 Regular substitution of lower-GI foods, such as whole grains, for higher-GI refined foods may thus help prevent excess weight gain.

Lifestyle changes that may be helpful: Many doctors give overweight patients a pill, a pep talk, and a pamphlet about diet and exercise, but that combination leads only to minor weight loss.18 When overweight people attend group sessions aimed at changing eating and exercise patterns, keep daily records of food intake, and exercise and eat a specific low-calorie diet, the outcome is much more successful. Group sessions where participants are given information and help on how to make lifestyle changes appear to improve the chances of losing weight and keeping it off. Such changes may include shopping from a list, storing foods out of sight, keeping portion sizes under control, and avoiding fast-food restaurants.

Exercise has been found to enhance the effectiveness of low-calorie diets.19 In addition, studies have shown that exercise alone (without dietary restriction) can promote weight loss in obese people.20 On the other hand, a review of numerous studies found that the typical regimen of three to five hours per week of exercise generally had little effect on weight loss, and may, in the case of resistance exercise, even increase weight slightly.21 Exercise appears to have a more consistent ability to enhance loss of fat tissue, specifically, as well as to preserve non-fat tissue in the body (particularly resistance training, such as weight-lifting). Preliminary research suggests that the most significant contribution by exercise may be in helping to maintain weight loss following a diet.22

People who experience “weight cycling” (repetitive weight loss and gain) have a tendency toward binge eating (periods of compulsive overeating, but without the self-induced vomiting seen in bulimia), according to a review of numerous studies focusing on weight loss.23 The researchers also found an association between weight cycling and depression or poor body image. The most successful weight-loss programs (in which weight stays off, mood stays even, and no binge eating occurs), appear to use a combination of moderate caloric restriction, moderate exercise, and behavior modification, including examination and adjustment of eating habits.

Nutritional supplements that may be helpful: Diets that are low in total calories may not contain adequate amounts of various vitamins and minerals. For that reason, taking a multiple vitamin-mineral supplement is advocated by proponents of many types of weight-loss programs, and is essential when calorie intake will be less than 1,100 calories per day.24

Pyruvate, a compound that occurs naturally in the body, might aid weight-loss efforts.25 A controlled trial found that pyruvate supplements (22–44 grams per day) enhanced weight loss and resulted in a greater reduction of body fat in overweight adults consuming a low-fat diet.26 Three controlled trials combining 6–10 grams per day of pyruvate with an exercise program reported similar effects on weight loss and body fat.27 28 29 Animal studies suggest that pyruvate supplementation leads to weight loss by increasing the resting metabolic rate.30

5-hydroxytryptophan (5-HTP), the precursor to the neurotransmitter serotonin, has been shown in three short-term controlled trials to reduce appetite and to promote weight loss.31 32 33 In one of these trials (a 12-week double-blind trial), overweight women who took 600–900 mg of 5-HTP per day lost significantly more weight than did women who received placebo.34 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 to 0.2 pounds in the placebo group.35

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.36 Participants in the trial 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 (6.34 pounds) and lowered their percentage of body fat (1.8%) further compared to those taking a placebo. These results may have been due to increases in 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.

The amino acid L-carnitine may help promote weight loss. In a preliminary trial of overweight adolescents participating in a diet and exercise program, those who took 1,000 mg of L-carnitine per day for three months lost significantly more weight than those who took a placebo.37 A weakness of this trial, however, was the fact that average starting body weight differed considerably between the two groups. Additional research is needed to confirm these preliminary findings.

Spirulina, a type of algae, is a rich source of protein, vitamins, minerals, and essential fatty acids. In one double-blind trial, overweight people who took 2.8 grams of spirulina three times per day for four weeks experienced only small and statistically nonsignificant weight loss.38 Thus, although spirulina had been promoted as a weight-loss aid, the scientific evidence supporting its use for this purpose is weak.

The mineral chromium plays an essential role in the metabolism of carbohydrates and fats and in the action of insulin. Chromium, in a form called chromium picolinate, has been studied for its potential role in altering body composition. Chromium has primarily been studied in body builders, with conflicting results.39 In people trying to lose weight, two double-blind trials have found no effect of chromium picolinate on weight loss,40 41 though in one of these trials lean body mass that was lost during a weight-loss diet was restored by continuing to supplement chromium after the diet.

(-)-Hydroxycitric acid (HCA), extracted from the rind of the Garcinia cambogia fruit grown in Southeast Asia, has a chemical composition similar to that of citric acid (the primary acid in oranges and other citrus fruits). Preliminary studies in animals suggest that HCA may be a useful weight-loss aid.42 43 HCA has been demonstrated in the laboratory (but not yet in clinical trials with people) to reduce the conversion of carbohydrates into stored fat by inhibiting certain enzyme processes.44 45 Animal research indicates that HCA suppresses appetite and induces weight loss.46 47 48 49 However, a recent double-blind trial found that people who took HCA while eating a low-calorie diet for 12 weeks lost no more weight than those taking a placebo.50 A double-blind trial of Garcinia cambogia (2.4 grams dry extract, containing 50% hydroxycitric acid) found that the extract did not increase energy expenditure; it was therefore concluded that this extract showed little potential for the treatment of obesity at this amount.51

Some,52 53 but not all,54 55 clinical trials have found that DHEA supplementation lowers fat mass without reducing total body weight.56 In one trial, the reduction in fat mass occurred in men but not in women.57

Are there any side effects or interactions? Refer to the individual supplement for information about any side effects or interactions.

Herbs that may be helpful: Ephedra sinica, commonly known as ma huang, is a central nervous system stimulant. Double-blind trials have shown that ephedra, particularly when combined with caffeine, promotes weight loss.58 However, a double-blind trial of ephedra alone (2 grams of powdered plant, 2% alkaloids) found that the herb failed to increase energy expenditure and showed little potential for the treatment of obesity at the amount used in this trial.59 While some studies have suggested that taking a combination of ephedra and caffeine may be safe for short-term weight loss, some doctors discourage the use of ephedra as a weight-loss aid because potentially dangerous side effects can occur with long-term use. Some of these side effects may be intensified when ephedra is combined with caffeine.60 61

Modest reductions in appetite have been found in healthy Japanese women and in white men when they consumed 10 grams of cayenne pepper along with meals in a clinical trial.62 A similar trial found that cayenne could increase metabolism of dietary fats in Japanese women.63 Both trials found the likely mechanism to be an increase in sympathetic nervous system activity.

Capsaicin, the major pungent ingredient in cayenne peppers, is thought to suppress appetite.64 A recent study has shown that a spicy food meal containing capsaicin may reduce food intake by about 200 calories.65

The herb guaraná contains caffeine and the closely related alkaloids theobromine and theophylline; these compounds may curb appetite and increase weight loss. Caffeine’s effects are well known and include central nervous system stimulation, increased metabolic rate, and a mild diuretic effect.66 In a double-blind trial, 200 mg per day of caffeine was, however, no more effective than a placebo in promoting weight loss.67 Because of concerns about potential adverse effects, many doctors do not advocate using caffeine or caffeine-like substances to reduce weight.

Green tea extract rich in polyphenols (epigallocatechin gallate, or EGCG) may support a weight-loss program by increasing energy expenditure. Healthy young men who took two green tea capsules (containing 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.68 Green tea extract thus seems to have the potential to influence body weight, although controlled trials on weight loss in humans are needed to further explore these preliminary observations.

Coupled with exercise in a double-blind trial, a combination of guggul, phosphate salts, hydroxycitrate, and tyrosine has been shown to improve mood with a slight tendency to improve weight loss in overweight adults.69 Daily recommendations for guggul are typically based on the amount of guggulsterones in the extract. A common intake of guggulsterones is 25 mg three times per day. Most guggul extracts contain 5–10% guggulsterones and can be taken daily for 12 to 24 weeks.

Although clinical trials are lacking, there are modern references to use of the herb coleus for weight loss.70 Coleus extracts standardized to 18% forskolin are available, and 50–100 mg can be taken two to three times per day. Fluid extract can be taken in the amount of 2–4 ml three times per day.

A combination of bitter orange extract (Citrus aurantium), caffeine, and St. John’s wort (Hypericum perforatum) has been shown to be superior to placebo or no treatment in promoting weight loss in people eating a low-fat diet.71 In a double-blind trial, healthy obese adults who took bitter orange extract (975 mg of standardized extract per day), caffeine (528 mg per day), and St. John’s wort (900 mg of standardized extract per day) for six weeks lost an average of three pounds more than people taking placebo or receiving no treatment.

One double-blind trial found that women consuming 20 grams of psyllium before a meal was associated with a decrease intake of fat and increased feelings of fullness following a meal.72 These effects are likely due to the high fiber content of psyllium.

Are there any side effects or interactions? Refer to the individual herb for information about any side effects or interactions.

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