Losing weight can dramatically improve your emotional and physical health, but it can be a slow process. So it’s no wonder that 15% of American adults use diet supplements to boost weight loss, opting for a range of products that claim to decrease appetite, block fat absorption, or increase metabolism.
Currently, most weight loss experts do not recommend many products marketed as weight loss supplements because of a lack of evidence. Also certain diet supplements, including ephedra, may cause heart attack and stroke. (Ephedra, also known as ma huang, was banned by the FDA in 2004 for sale in the U.S.)
However, there are some proven weight loss supplements available. Which weight loss supplements may be safe and helpful during a diet? Here’s a rundown on six products you can buy at most health food or drugstores that have some weight loss evidence behind them:
- Conjugated linoleic acid (CLA)
- Green tea extract
- Meal replacements
- Orlistat, an over-the-counter weight loss drug
Remember, of course, that you should always check with your doctor before taking any type of supplement. Even supplements can have side effects and may interfere with medications you take. And, when it comes to weight loss, there are no quick fixes. A healthy eating plan and regular physical exercise should be the foundation of any weight loss program.
Weight Loss Supplements: Calcium
Bone health may be the first thing that comes to mind when you hear the word calcium, but this mineral may also help you lose fat while preserving muscle.
Research is mixed. Some studies have not found a relationship between calcium intake and weight loss.
However, “there have been several studies that have shown benefits from three daily servings of low-fat dairy foods, including weight loss,” says Toby Smithson, RD, national spokesman for the American Dietetic Association. Those studies “showed more weight loss from low-fat dairy foods combined with a reduced-calorie diet than from calcium supplements,” Smithson notes.
That’s not to say calcium supplements might not help you in your weight loss efforts. In one analysis, researchers found that dieting women who received 1,000 mg of calcium supplements each day lost, on average, more weight and more body fat than women taking a placebo. Although the differences in the amount of weight and fat lost by the two groups were not significant, the trend suggests there could be a relationship between calcium supplements and weight loss.
Because calcium and weight loss studies have found conflicting results, you can expect a lot more research on this subject. Researchers who have found a connection between calcium and weight loss hypothesize that dietary calcium might play a role in the breakdown and storage of fat. Additionally, the weight loss that has sometimes been observed in people who eat dairy may have something to do with specific dairy proteins and magnesium, another important mineral abundant in dairy products. But so far, these hypotheses are unproven.
Weight Loss Supplements: Conjugated Linoleic Acid (CLA)
Using a type of fat as a weight loss supplement might sound counterintuitive. But it might work, too. Conjugated linoleic acid, a fatty acid that occurs naturally in small amounts in dairy products and red meat, is a diet supplement that may work, but can also have some concerning side effects.
Some studies have found that CLA diet supplements can help you lose body fat and increase lean body mass. When a group of overweight people took 3.2 grams of CLA each day for six months, they lost more body fat than people taking a placebo and gained less holiday weight during the winter months.
Many experts are calling for more clinical studies to learn more about the effectiveness and safety of CLA as a weight loss supplement. What’s the best way for people to reap the benefits of this diet supplement? Can you take too much? Is it safe?
Research on CLA has shown some concering side effects, mostly because it is a special type of fat similar to trans fats. For example, blood tests that follow inflammation can be higher in some people taking CLA, and it may adversely affect cholesterol levels and liver tests. Be sure to talk with your doctor before taking CLA as a diet supplement.
Weight Loss Supplements: Fiber
When it comes to dropping pounds, weight loss supplements that help keep you full can make it easier to cut back on the amount of food you eat. And when it comes to feeling full, fiber is your friend.
“Things that delay gastric emptying and stay in the stomach longer theoretically will make you feel fuller for a longer period of time,” says Sasha Stiles, MD, an obesity expert at Tufts Medical Center. “There’s enough fairly good research to show that an appropriate amount of fiber, such as bran or psyllium, can do this. Don’t take too much, though, because it can stop you up.”
A recent study found that overweight and obese people who took a fiber diet supplement each day reported less hunger after meals than people taking a placebo, and there was a trend for those using a fiber supplement to lose more weight.
If you decide to increase your fiber intake from food or diet supplements, be sure to add fiber to your diet slowly. Drink plenty of fluids to avoid becoming constipated.
The National Academy of Sciences Institute of Medicine recommends that men under age 50 consume 38 grams of fiber a day, and 30 grams a day after age 50. Women under age 50 should consume 25 grams of fiber per day, and 21 grams per day after age 50. Most people only get about half of this amount.
Weight Loss Supplements: Green Tea Extract
You may have already heard that green tea is loaded with healthy antioxidants, but did you know it might help you lose weight, too?
Although Smithson cautions that there are not enough human studies to prove the effectiveness of green tea extract as a weight loss supplement, she tells WebMD “…there is some thought that regular consumption may promote weight loss by adjusting resting energy usage and increasing the use of energy. The components in green tea extract that have shown some effect on lowering body weight are catechins, caffeine and theanine.” Decaffeinated green tea probably won’t work as well as regular green tea.
Not all studies agree. But one recent report found that daily green tea extract supplements helped obese men and women lose weight and lower their body mass index (BMI — an indicator of body fat). It might also help people keep off weight once they’ve lost it. Green tea extract also helped reduce amounts of dangerous belly fat, which has been linked to an increased risk of death. Not only that, green tea extract lowered blood pressure and LDL, or “bad,” cholesterol at the same time.
Weight Loss Supplements: Meal Replacements
Experts agree: The most proven weight loss supplements are meal replacements, including bars and shakes.
But, they only work when used as directed. In many plans, this means substituting a calorie-controlled meal replacement for breakfast and lunch, perhaps with the addition of fresh fruit. Then enjoy a portion-controlled dinner of around 500 calories.
“There’s very good scientific literature around meal replacements that is encouraging — this is a strategy for some people that is efficient and safe,” says Steven R. Smith, MD, professor and assistant to the executive director for clinical research at the Pennington Biomedical Research Center.
“For folks who adopt that strategy, there’s pretty good long-term success,” says Smith. “The reason for that is that it’s simple, it’s structured and it allows people to continue to enjoy food with their evening meal.”
Weight Loss Supplements: Over-the-Counter Orlistat
Technically, Orlistat is a medicine, not a supplement. However, it’s approved by the FDA for sale without a prescription (brand name Alli), thus many people consider it a diet supplement.
“This is the one that has the data behind it,” says Caroline Apovian, MD, the director of the Center for Nutrition and Weight Management at Boston Medical Center. “It blocks 25% of the fat calories eaten from being absorbed. You can hang your hat on this data.”
Orlistat helps people lose weight as long as they also follow a diet and exercise. But it can have some unpleasant intestinal side effects. Be sure to follow the product’s recommendations to limit fat intake to minimize potentially embarrassing problems with anal leakage and gas.
General Suggestions for Using Weight Loss Supplements
If you do use weight loss supplements, be aware that the vast majority of products sold as diet supplements are not regulated by the FDA. To make sure that the product you are purchasing has undergone quality control testing, look for diet supplements that bear a United States Pharmacopeia (USP) seal or that have passed assembly on the Consumer Lab website.
Be sure to ask your doctor about taking weight loss supplements before you use them. Avoid products with excessive levels of caffeine, which can cause side effects, such as increased heart rate and blood pressure.
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