Principal Proposed Natural Treatments
Chromium. Chromium is a mineral the body needs in
only small amounts, but it is important to human nutrition. Although it has
principally been studied for improving blood sugar control in people with
diabetes, chromium has also been tried for reducing total weight and body fat
percentage, with some success. Both of these potential benefits involve chromium’s
effects on insulin. Before an explanation of how chromium may help,
some background information on how the body controls its blood sugar levels will
be provided here.
The body needs a constant level of glucose (sugar) in the blood. When a
person digests a carbohydrate meal, glucose levels rise. Protein meals have the
same effect, although to a lesser extent. The body responds by secreting insulin.
Insulin causes the cells of the body to absorb glucose out of the blood, thereby
reducing circulating blood sugar.
Once cells have taken in glucose, they can burn it for energy or convert it to a storage form. Liver and muscle cells can store a limited amount of glucose as glycogen. Fat cells can convert unlimited amounts of glucose into energy stored as fat.
The process also goes the opposite way. When the body has used up the food from its last meal, blood glucose levels drop. Just as the body does not respond well to glucose levels that are too high, low glucose levels also cause problems. The body, in response, applies its control mechanisms to raise blood sugar levels. It does so by reducing its output of insulin and also by raising levels of another hormone called glucagon. The net effect is that energy storage depots are mobilized. Glycogen is converted back into glucose. In addition, fat cells release their contents into the bloodstream to supply an alternative energy source. In summary, high insulin levels build fat, whereas low insulin levels break down fat.
Based on this push-pull effect, to lose weight, one should keep insulin levels low. Dieting is the most obvious method of reducing insulin. When a person does not take in enough calories to supply the body’s daily needs, insulin levels fall and the body breaks down fat cells. Exercising is another method to reduce insulin; by increasing the body’s energy requirements, exercise causes insulin levels to fall and fat cells to break down.
It is difficult to consistently use more energy than one takes in. Hunger takes over, and a person wants to eat. If there were some way to trigger fat breakdown without going hungry, it would make weight loss much easier.
There is another important connection between insulin and weight to consider.
Persons who weigh too much often develop insulin
resistance. In this condition, certain cells of the body
become less sensitive to insulin. The body senses this and, thus, increases
insulin production until it overcomes the resistance. It is possible that fat
cells respond to these increased levels of insulin by storing even more fat.
Chromium is thought to improve the body’s responsiveness to insulin. Combining this belief with the insulin-weight connections, some researchers have proposed that chromium may assist in decreasing weight or improving body composition (the ratio of fatty tissue to lean tissue).
The main argument is the following: Chromium increases insulin sensitivity. This causes levels of insulin to fall. With reduced amounts of insulin in the blood, fat cells are less inclined to store fat, so weight loss may become easier. In addition, there is some evidence that chromium partially blocks insulin’s effects on fat cells, interfering with its fat-building effect. This could also promote weight loss. Another small study suggests that chromium may work by influencing the brain and its role in appetite and food cravings.
There are several flaws in these arguments, though. For example, even very small amounts of insulin in the blood effectively suppress fat breakdown. Another problem is that during insulin resistance, fat cells also appear to become resistant to insulin. Insulin resistance, in other words, might be a natural method of regulating weight gain. Chromium supplements might have the undesired effect of increasing the ability of fat cells to respond to insulin, helping them to better store fat.
However, theory takes one only so far. It is more important to review the results of studies in which people were given chromium supplements to reduce their weight.
About ten well-designed, double-blind, placebo-controlled trials have evaluated chromium’s potential benefit for weight loss. In the largest study, 219 people were given either placebo, 200 micrograms (mcg) of chromium picolinate daily, or 400 mcg of chromium picolinate daily. Participants were not advised to follow any particular diet. For seventy-two days, people taking chromium experienced significantly greater weight loss (more than 2.5 pounds versus about 0.25 pound) than those not taking chromium. Persons taking chromium actually gained lean body mass, so the difference in loss of fatty tissue was greater: more than 4 pounds versus less than 0.50 pound. However, a high dropout rate makes the results of this study somewhat unreliable.
In a smaller double-blind study by the same researcher, 130 moderately overweight persons attempting to lose weight were given either placebo or 400 mcg of chromium daily. Although hints of benefit were seen, they were too slight to be statistically significant. Several other small, double-blind, placebo-controlled studies also failed to find evidence of the benefit of chromium picolinate as an aid to weight loss. One study failed to find benefit with a combination of chromium and conjugated linoleic acid.
When larger studies find positive results and smaller studies do not, it often indicates that the treatment under study is only weakly effective. This may be the case with chromium as a weight-loss treatment.
Pyruvate. Pyruvate supplies the body with pyruvic
acid, a natural compound that plays important roles in the manufacture and use of
energy. Theoretically, taking pyruvate might increase the body’s metabolism,
particularly of fat.
Several small studies enrolling about 150 people have found evidence that pyruvate or DHAP (a combination of pyruvate and the related substance dihydroxyacetone) can aid weight loss or improve body composition, or both. For example, in a six-week, double-blind, placebo-controlled trial, fifty-one people were given either pyruvate (6 grams [g] daily), placebo, or no treatment. All participated in an exercise program. In the treated group, significant decreases in fat mass (2.1 kilograms [kg]) and percentage body fat (2.6 percent) were seen, along with a significant increase in muscle mass (1.5 kg). No significant changes were seen in the placebo or nontreatment groups.
Another placebo-controlled study (blinding not stated) used a much higher dose of pyruvate (22 to 44 g daily, depending on total calorie intake). In this trial, thirty-four slightly overweight people were put on a mildly weight-reducing diet for four weeks. Subsequently, one-half were given a liquid dietary supplement containing pyruvate. In six weeks, people in the pyruvate group lost a small amount of weight (about 1.5 pounds), while those in the placebo group did not lose weight. Most of the weight loss came from fat.
Another placebo-controlled study evaluated the effects of DHAP when people who had previously lost weight increased their calorie intake. Seventeen severely overweight women were put on a restricted diet as inpatients for three weeks, during which time they lost approximately 17 pounds. They were then given a high-calorie diet. Approximately one-half of the women also received 15 g of pyruvate and 75 g of dihydroxyacetone daily. The results found that after three weeks of this weight-gaining diet, persons receiving the supplements gained only about 4 pounds, compared to about 6 pounds in the placebo group. Close evaluation showed that pyruvate specifically blocked the regain of fat weight. Larger studies (one hundred participants or more) are needed, however, to establish the benefits of pyruvate for weight loss.
Fiber. Dietary fiber is important to many intestinal
tract functions, including digestion and waste excretion. It also appears to have
a mild cholesterol-lowering effect and might help reduce the risk of some kinds of
cancer (although the evidence is a bit contradictory).
Fiber might also be useful for losing weight. It is thought to work in a simple way by filling the stomach and causing a feeling of fullness, while providing little to no calories. Fiber might also interfere with the absorption of fat.
There are two kinds of fiber: soluble fiber, which swells up and holds water, and insoluble fiber, which does not. Soluble fiber is found in psyllium seed (sold as a laxative), 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.
Several double-blind, placebo-controlled studies have evaluated fiber supplements as an aid to weight loss. The results have been somewhat inconsistent, but in general it appears that some forms of fiber may slightly enhance weight loss.
In one of the largest studies, ninety-seven mildly overweight women on a strict low-calorie diet were given either placebo or an insoluble fiber (type not stated) three times daily for eleven weeks. Women given fiber lost almost 11 pounds compared to about 7 pounds in the placebo group. Participants using the fiber reported less hunger.
Researchers were not finished with the study participants. For an additional sixteen weeks, the diet was changed to one that supplied more calories. As expected, participants regained some weight during this period. Nonetheless, by the end of the sixteen weeks, persons taking fiber were still 8 pounds lighter than at the beginning of the study, while those taking placebo were only 6 pounds lighter.
Another study evaluated whether the benefits of dietary fiber endure in six months of dieting. This double-blind trial of fifty-two overweight people found that the use of insoluble dietary fiber (in a product made from beet, barley, and citrus) almost doubled the degree of weight loss compared with placebo. Once more, participants using the fiber supplement reported less hunger.
Two other double-blind, placebo-controlled studies evaluated a similar insoluble fiber product. The first enrolled sixty moderately overweight women and put them on a 1,400-calorie diet along with placebo or fiber for two months. The other study was similar but enrolled only forty-five women and followed them for three months. The results of both studies again showed improved weight loss and reduced feelings of hunger in the treated groups. However, a twenty-four-week study of fifty-three moderately overweight persons found no difference in effect between placebo and 4 g of insoluble fiber daily. Another study failed to find benefit with either of two soluble fiber supplements (methylcellulose or pectin plus beta glucan) in terms of weight, hunger, or satiety.
Glucomannan, a source of soluble dietary fiber from the
tubers of Amorphophallus konjac, has also been tried for weight
loss, with positive results in adults. In a double-blind, placebo-controlled trial
of twenty overweight persons, researchers found that the use of glucomannan
significantly improved weight loss in an eight-week period. Benefits were also
seen in a double-blind, placebo-controlled trial of twenty-eight overweight
persons who had just had a heart attack. However, another trial studied the
effectiveness of glucomannan as a weight-loss agent in sixty overweight children
and found no benefit.
An eight-week, double-blind, placebo-controlled trial of fifty-nine overweight
people evaluated the effects of chitosan, a mostly insoluble fiber from
crustaceans, taken at a dose of 1.5 g before each of the two biggest meals of the
day. No special diets were assigned. The results showed that, on average,
participants in the placebo group gained more than 3 pounds during the study,
while those taking chitosan lost more than 2 pounds. However, a subsequent
twenty-four-week, double-blind, placebo-controlled study of 250 people using the
same dosage of chitosan failed to find benefit. Negative results were also seen in
an eight-week, double-blind, placebo-controlled trial of fifty-one women given
1,200 mg twice daily and in a twenty-eight-day double-blind trial of thirty
overweight people using 1 g twice daily. Although benefits have shown up in other
studies, the balance of evidence indicates that chitosan probably does not work.
Furthermore, chitosan supplements may at times contain toxic levels of
arsenic.
A few trials have evaluated the effects only on hunger and satiety rather than on
weight loss. One study found that the soluble fiber pectin (from
apples) reduces hunger sensations. Another found that the soluble fiber guar gum
slows stomach emptying and increases the sensation of fullness. However, a later
study evaluated the effects of guar gum in twenty-five women undergoing a
weight-loss program and found no influence on hunger. In another study, consuming
fiber from barley led to an increase in calorie consumption.
The optimum dose of fiber and the proper time to take it have not been determined. In the first three studies noted, insoluble fiber supplements were given twenty to thirty minutes before each meal at a dose of about 2.3 g, along with a large glass of water.
Fiber supplements should be taken with water to keep the fiber from blocking the digestive tract. Even when they are used properly, mild gastrointestinal side effects such as gas and bloating may occur. As a positive side effect, fiber supplements may reduce high levels of cholesterol and blood pressure.
Other Proposed Treatments
5-hydroxytryptophan. The supplement 5-hydroxytryptophan
(5-HTP) is thought to affect serotonin levels. Because
serotonin is thought to play a role in weight regulation, 5-HTP has been
investigated as a possible weight-loss aid. A total of four small, double-blind,
placebo-controlled clinical trials have been reported.
The first of these, a double-blind crossover study, found that the use of 5-HTP (at a daily dose of 8 mg per kilogram of body weight) reduced caloric intake even though the nineteen participants made no conscious effort to eat less. Participants given placebo consumed about 2,300 calories per day, while those taking 5-HTP ate only 1,800 calories daily. The use of 5-HTP appeared to lead to a significantly enhanced sense of satiety after eating. In five weeks, women taking 5-HTP effortlessly lost more than 3 pounds.
A follow-up study by the same research group enrolled twenty overweight women who were trying to lose weight. Participants received either 5-HTP (900 mg per day) or placebo for two consecutive six-week periods. In the first period, there was no dietary restriction, while in the second period, participants were encouraged to follow a defined diet that was expected to lead to weight loss.
Participants receiving placebo did not lose weight during either period. However, those receiving 5-HTP lost about 2 percent of their initial body weight during the no-diet period and an additional 3 percent while on the diet. Thus, a woman with an initial weight of 170 pounds lost about 3.5 pounds after six weeks of using 5-HTP without dieting and another 5 pounds while dieting. Once again, participants taking 5-HTP experienced quicker satiety. Similar benefits were seen in a double-blind study of fourteen overweight women given 900 mg of 5-HTP daily.
Finally, a double-blind, placebo-controlled study of twenty overweight persons with adult-onset (type 2) diabetes found that the use of 5-HTP (750 mg per day) without intentional dieting resulted in about a 4.5-pound weight loss in two weeks. The use of 5-HTP reduced carbohydrate intake by 75 percent and fat intake to a lesser extent.
All of these studies, however, were performed by a single research group. In science, results are not considered valid until they are independently replicated by different researchers. In addition, all these studies were small in size. For these reasons, further research is necessary before 5-HTP can be considered a proven weight-loss agent.
Garcinia cambogia.
Hydroxycitric
acid (HCA), a derivative of citric acid, is found primarily
in a small, sweet, purple fruit called Garcinia cambogia, the
Malabar tamarind. Although animal and test-tube studies and one human trial
suggest that HCA might encourage weight loss, other studies have found no benefit.
In an eight-week, double-blind, placebo-controlled trial of sixty overweight
people, the use of HCA at a dose of 440 mg three times daily produced significant
weight loss compared with placebo.
In contrast, a twelve-week, double-blind, placebo-controlled trial of 135 overweight persons, who were given either placebo or 500 mg of HCA three times daily, found no effect on body weight or fat mass. However, this study has been criticized for using a high-fiber diet, which is thought to impair HCA absorption.
Other small placebo-controlled studies found HCA had no effect on metabolism, appetite, or weight. It is not clear whether G. cambogia is an effective treatment for weight loss.
Caffeine and ephedrine. Caffeine and
ephedrine (found in ephedra, an herb also known as ma huang)
are central nervous system stimulants. Considerable evidence suggests
ephedrine-caffeine combinations can modestly assist in weight loss.
For example, in a double-blind, placebo-controlled trial, 180 overweight people were placed on a weight-loss diet and given either ephedrine-caffeine (20 mg/200 mg), ephedrine alone (20 mg), caffeine alone (200 mg), or placebo three times daily for twenty-four weeks. The results showed that the ephedrine-caffeine treatment significantly enhanced weight loss, resulting in a loss of more than 36 pounds compared to only 29 pounds in the placebo group. Neither ephedrine nor caffeine alone produced any benefit. Contrary to some reports, participants did not develop tolerance to the treatment. For the entire six months of the trial, the treatment group maintained the same relative weight loss advantage over the placebo group. While this study found benefit only with caffeine-ephedrine and not with ephedrine alone, other studies have found that ephedrine alone also offers some weight-loss benefits.
It is not known how ephedrine-caffeine works. However, caffeine has actions that cause fat breakdown and enhance metabolism. Ephedrine suppresses appetite and increases energy expenditure. The combination appears to produce synergistic effects, with appetite suppression probably the most important overall factor.
Ephedrine presents serious medical risks and should be used only under physician supervision. In the United States, the sale of ephedrine-containing products is banned.
Medium-chain triglycerides. Some evidence suggests that
consumption of medium-chain triglycerides (MCTs) might enhance the body’s
tendency to burn fat. This has led to investigations of MCTs as a weight-loss aid.
However, the results of clinical trials have been fairly unimpressive.
In a four-week, double-blind, placebo-controlled trial, sixty-six women were put on a diet very low in carbohydrates to induce a state called ketosis. One-half of the women received a liquid supplement containing ordinary fats; the other one-half received a similar supplement in which the ordinary fats were replaced by MCTs.
The results indicated that the MCT supplement significantly increased the rate of “fat burning” during the first two weeks of the trial and also reduced the loss of muscle mass. However, these benefits declined during the last two weeks of the trial, which suggests that the effects of MCTs are temporary. Studies that involved substituting MCTs for ordinary fats in a low- calorie diet have shown minimal relative benefits at best.
A related supplement called structured medium- and long-chain triacylglycerols (SMLCT) has been created to provide the same potential benefits as MCTs, but in a form that can be used as cooking oil. In a preliminary double-blind trial, SMLCT showed some promise as a “fat burner.”
Other approaches to weight loss. A special type of fat known as diacylglycerol has shown promise as a weight-loss aid. For example, in a twenty-four-week, double-blind, placebo-controlled study, 131 overweight men and women were placed on a weight-loss diet including supplementary foods containing either diacylglycerols or ordinary fats. The results showed that participants who were using diacylglycerols lost more weight than participants who were using ordinary fats. Diacylglycerols appear to be safe.
In four preliminary controlled trials, a patented, proprietary blend of fats added to yogurt has shown potential weight-loss benefit. Also, Korean pine nut oil (PinnoThinac), which is high in free fatty acids, was shown in one study (that compared the pine nut oil to olive oil) to reduce the appetite of forty-two overweight women.
Beans partially interfere with the body’s ability to digest carbohydrates, which is why they cause flatulence. Based on this process, products containing the French white bean Phaseolus vulgaris have been widely marketed as weight-loss aids. However, published studies have generally failed to find these carbohydrate blockers effective for this purpose. According to one manufacturer, more concentrated extracts of P. vulgaris, taken in higher doses, actually can work. The evidence for this claim, until 2007, rested entirely on unpublished studies not independently verified.
A relevant trial was at last published in 2007. In this double-blind,
placebo-controlled study, sixty slightly overweight people were given either
placebo or a phaseolus extract once daily, thirty minutes before a main
meal rich in carbohydrates. The results of the thirty-day study indicated that
phaseolus treatment led to a significantly greater reduction of body weight and
improvement of lean/fat ratio compared with placebo.
Some evidence suggests that the supplements creatine and
colostrum may each slightly improve body composition
(fat-to-muscle ratio) compared with placebo among persons undergoing an exercise
program. It has been suggested too that calcium supplements, or high-calcium
diets, may slightly enhance weight loss, but evidence is more negative than
positive. However, because bones may grow thin during rapid weight loss, it may
make sense to take calcium supplements when intentionally losing weight. (When
weight loss is induced by exercise rather than diet, bone loss does not seem to
occur.)
A six-month double-blind study found that the supplement dehydroepiandrosterone (DHEA) at a dose of 50 mg daily may help decrease abdominal fat and improve insulin sensitivity (thereby potentially helping to prevent diabetes) in the elderly. However, another study failed to find DHEA at 40 mg twice daily helpful for weight loss in severely overweight adolescents. A supplement related to DHEA, 3-acetyl-7-oxo-dehydroepiandrosterone (also called 7-oxy or 7-keto-DHEA), has shown some promise for enhancing weight loss.
Results of two small, double-blind, placebo-controlled studies suggest that vitamin C supplements might aid in weight loss. A related study found that marginal vitamin C deficiency might interfere with deliberate attempts to lose weight. Also, one small, double-blind study indicates that a concentrated extract of the herb Coleus forskohlii might increase the rate of fat burning.
A double-blind, placebo-controlled trial that enrolled 158 moderately overweight persons tested a mixture of chromium, cayenne, inulin (a nondigestible carbohydrate), and phenylalanine (an amino acid), and other herbs and nutrients. All participants lost weight in the four-week trial. Those using the supplement lost a bit more weight, but the difference was not mathematically significant. However, some positive news came from close examination of the results. Among those taking the supplement, a significantly higher percentage of the weight loss came from fat instead of muscle.
One study found benefit with a combination treatment containing niacin-bound chromium combined with Gymnema sylvestre and HCA. Another study reported weight-loss effects with a combination of HCA, pantothenic acid, chamomile, lavender, damask rose, and the Hawaiian herb Cananga odorata. A very small study hints that soy isoflavones might help reduce buildup of abdominal fat.
Weight-loss benefits were seen in a double-blind trial of 150 overweight people given either placebo or one of two doses of a combination therapy containing chitosan, chromium, and HCA. Benefits were also seen in a forty-five-day double-blind, placebo-controlled trial of forty-four overweight people that tested a combination product containing yerba mate, guarana, and damiana. Minimal benefits were seen in a twelve-week double-blind study evaluating a combination of asparagus, green tea, black tea, guarana, maté, kidney beans, Garcinia cambogia, and high-chromium yeast.
A double-blind, placebo-controlled study evaluated the effects of a mixture containing Citrus aurantium (bitter orange), caffeine, and St. John’s wort. C. aurantium contains various stimulant chemicals related to nasal spray decongestants. The results suggest that this combination might assist weight loss, but the study was so small (twenty-three participants divided into three groups) that the results mean little.
Ayurvedic herbs have shown some promise for weight loss. In a three-month, double-blind, placebo-controlled study, seventy overweight people were divided into four groups: placebo, Triphala guggul (a mixture of five Ayurvedic ingredients) plus Gokshuradi guggul (a mixture of eight Ayurvedic ingredients), T. guggul plus Sinhanad guggul (a mixture of six Ayurvedic herbs), or T. guggul plus Chandraprabha vati (a mixture of thirty-six Ayurvedic ingredients). Reportedly, all three Ayurvedic ingredients produced significant weight loss and improvements in cholesterol compared with placebo; furthermore, the improvements produced by the respective treatments were close to identical.
One study failed to find benefit with a proprietary mixture of astragalus, gallic acid, ginger, red sage, rhubarb, and turmeric. Studies attempting to determine whether evening primrose oil can aid in weight loss have yielded mixed results. Another study failed to find benefit with the edible cactus Caralluma fimbriata.
Conjugated
linoleic acid (CLA) is a mixture of different isomers, or
chemical forms, of linoleic acid. CLA has been proposed as a fat-burning
substance, improving lean-to-fat-mass ratios and reducing total fat mass, but on
balance, the benefit appears to be slight. Also, some studies have raised concerns
that the use of CLA by overweight people could raise insulin resistance and
therefore increase the risk of diabetes. In addition, the use of CLA might impair
endothelial function and levels of C-reactive protein and, thereby, increase
cardiovascular risk.
One study found that the topical application of glycyrrhetinic acid, a constituent of licorice, can reduce fat thickness in the thigh. A mixture of the herbs Magnolia officinalis and Phellodendron amurense is said to help reduce stress-induced overeating, but the only supporting evidence for this claim is a study too small to provide meaningful results. The herb Hoodia gordonii, often known simply as hoodia, has been marketed as a weight-loss treatment. However, the evidence that it works is limited to one small unpublished trial funded by the manufacturer.
Hypnosis is popular as an aid to weight loss. However, a
careful analysis of published studies suggests that the benefits are slight at
best. Although acupuncture is widely used for weight loss, the evidence
from published studies is incomplete and inconsistent.
One double-blind study failed to find capsaicin (the “hot” in cayenne pepper) helpful for preventing weight regain after weight loss, but it did seem to cause some increase in fat metabolism. A rather theoretical study found that two ingredients in green tea may interact to increase metabolism, and on this basis green tea became a popular weight control supplement. However, other evidence indicates that if green tea increases metabolism, the effect is extremely small. One study conducted in Thailand reported weight-loss benefits with green tea; however, a Dutch study failed to find green tea helpful for preventing weight regain after weight loss. In another study, the use of green tea failed to produce significant weight loss in overweight women with polycystic ovary syndrome.
Green tea extract enriched with catechins (an active ingredient in green tea) has done better, enhancing weight loss in one substantial but somewhat flawed trial. Oolong tea enriched with green tea catechins found some apparent weight-loss benefit. However, a study in overweight Japanese children did not support the effectiveness of green tea catechins for weight reduction. Similar results were obtained in another placebo-controlled trial involving seventy-eight overweight women after twelve weeks of treatment.
Other supplements that have been studied but not found effective include spirulina, L-carnitine, and oligomeric proanthocyanidin complexes from grape seed. An enormous number of other supplements are marketed for weight loss, but they are sold without meaningful supporting evidence. For example, certain supplements are said to be lipotropic, meaning that they help the body metabolize fat or slow down the rate at which it is stored. Vitamins B5 and B6, biotin, choline, inositol, lecithin, and lipoic acid are often placed in this category. However, there is no real evidence that they will help one lose weight.
A number of amino acids, including phenylalanine, tyrosine, methionine, and glutamine, are said to reduce hunger. Because the herb kava appears to be helpful for anxiety, it has been proposed as a treatment for mood-related overeating. The antidepressant herb St. John’s wort has been recommended with much the same reasoning.
Seaweeds such as kelp, bladderwrack, and sargassi are often added to diet formulas, under the assumption that they will affect the thyroid gland through their iodine content. (An underactive thyroid can cause weight gain.) However, the effect of iodine on thyroid function depends on whether a person is iodine deficient. Excess iodine can actually suppress the action of the thyroid. The herb guggul (Commiphora mukul) is often claimed to enhance thyroid function, and for this reason it is often sold as a weight-loss agent. However, there is little evidence that it actually affects the thyroid, and a small double-blind trial found it no more effective than placebo for weight loss.
Numerous herbs and supplements with potential or known effects on insulin or blood sugar levels are widely added to weight-loss formulas, again without any evidence that they are effective. These herbs and supplements include alfalfa, Anemarrhena asphodeloides, arginine, Azadirachta indica (neem), bilberry leaf, bitter melon (Momordica charantia), Catharanthus roseus, Coccinia indica, Cucumis sativus, Cucurbita ficifolia, Cuminum cyminum (cumin), Euphorbia prostrata, garlic, glucomannan, Guaiacum coulteri, Guazuma ulmifolia, guggul, holy basil (Ocimum sanctum), Lepechinia caulescens, Musa sapientum L. (banana), nopal cactus (Opuntia streptacantha), onion, Psacalium peltatum, pterocarpus, Rhizophora mangle, Salacia oblonga, salt bush, Spinacea oleracea, Tournefortia hirsutissima, Turnera diffusa, and vanadium.
Herbs with laxative or diuretic properties or reputations are also popular in weight-loss formulas, although they are unlikely to produce anything beyond a slight temporary effect. These include barberry, buchu, cascara sagrada bark, cassia powder, cleavers, cornsilk, couchgrass, dandelion root, fig, goldenrod, hydrangea root, juniper berry, peppermint, prune, senna leaf, tamarind, turkey rhubarb root, and uva ursi.
Herbs that are supposed to strengthen the body in general are found in many diet formulas, including ashwagandha, Cordyceps, Eleutherococcus, fo-ti, ginseng, maitake, reishi, schisandra, and suma.
Other herbs and supplements sometimes recommended for weight loss for reasons that are unclear include buckthorn, cayenne, chickweed, coenzyme Q10, cranberry, fennel, flaxseed, ginger, ginkgo, gotu kola, grape seed extract, hawthorn, licorice, milk thistle, parsley, passionflower, plantain, white willow, yellow dock, yucca, and zinc.
Numerous dietary methods have been proposed for aiding weight loss. The
Mediterranean
diet, which is relatively high in fiber and monounsaturated
fats (such as olive oil), has attracted attention as an effective method for
weight management. Two of the most popular alternative diets for weight loss are
low-carbohydrate diets and low-glycemic-index (low-GI)
diets. On average, it appears that all dietary weight-loss approaches are about
equally helpful, provided one sticks to the “rules.” However, it is possible that
a low-GI diet and the Mediterranean diet are more beneficial than a low-fat diet
in people with type 2 diabetes and prediabetes.
One study found that reducing one’s consumption of high-sugar beverages has a minor effect, if any. Also, it has often been suggested that a vegetarian diet enhances weight loss, but this has not been proven.
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