Can dietary supplements help with weight loss?


Can dietary supplements help with weight loss? Before investing your time and money in these products, it’s important to understand that no supplement to date can erase poor dietary choices or lack of physical activity. When my patients ask me about supplements for weight loss, I explain that there’s no good substitute for portion control and exercise. Any effects that supplements have on the amount of calories you burn or the way you metabolize fat are minimal and most don’t have enough reliable scientific evidence to prove their effectiveness.  

Here, I’ve reviewed six of the most commonly used supplements, how they work, if they’re effective and possible side effects of each. As with all supplements, there are potential drug nutrient interactions. Before taking any dietary or herbal supplement, talk to your doctor and registered dietitian.

1. Protein Bar/Powder

How it works: Protein powders and bars don’t cause weight loss but can create a greater feeling of satiety, which is what you want when you’re trying to lose weight. Keep in mind that you’ll be able to satisfy your appetite by having smaller, more frequent meals with protein sources at each, whether protein is in supplement form or natural food sources (for example: eggs, meat, dairy and beans).  
Effectiveness: Most clinical research studies that show significant weight loss have paired protein supplementation with a low-calorie diet. The studies showing no significant weight loss with protein supplements had no diet modification.
Side Effects: A common symptom is increased flatulence and abdominal bloating or loose stools. This is typically caused by sugar alcohols in some bars. As for protein powder in shakes, they’re made with different types of protein sources. If you’re lactose intolerant, you may want to choose one that’s lactose-free.

2. Green Tea Extract

How it works and effectiveness: The caffeine in this product can increase the calories you burn at a resting rate but there’s not enough reliable scientific evidence to prove its effectiveness for weight loss. Research on whether green tea extract is effective for weight loss is conflicting.
Side Effects: Green tea is tolerated well when consumed as a beverage. But, as with any supplement, there’s a long list of potential side effects with cardiovascular, endocrine, neurological and gastrointestinal systems. For a complete list of potential side effects, visit the Natural Medicines Database.

3. Chitosan

How it works: Chitosan is believed to block fat absorption in the intestines.
Effectiveness: Most research showing modest weight loss with chitosan was because it was paired with a low-calorie diet. In clinical research studies, taking chitosan alone without calorie restriction doesn’t appear to cause significant weight loss. 
Side Effects: Taken orally in recommended safe doses, chitosan appears to be tolerated well. The most notable potential side effects are increased abdominal discomfort with bloating and diarrhea.

4. Conjugated Linoleic Acid (CLA)

How it works: Conjugated Linoleic Acid might help reduce body fat deposits. Researchers believe that CLA increases the breakdown of fat and cell death. Some believe that it also inhibits the creation of fat in loose connective tissue. CLA can be found naturally in some dairy and beef products.
Effectiveness: There is some evidence supporting its use, but evidence is limited.
Side Effects: CLA appears to be tolerated well orally. Common side effects include upset stomach, nausea, diarrhea, loose stools and flatulence.

5. Glucomannan

How it works and effectiveness: Glucomannan is a dietary fiber made from the root of the konjac plant, which may promote satiety. Compared to other dietary fibers, it has greater proportions of soluble fiber and may increase the amount of calories lost through the soluble fiber binding to the cholesterol in your diet and excreting those fat calories through your stool. 
Side Effects: In clinical research when taken orally, glucomannan appears to be tolerated well. In some cases, loose stools, diarrhea, constipation, abdominal discomfort, bloating, nausea, vomiting and flatulence have been reported. In addition, when taken in tablet form, some esophageal and gastrointestinal blockages have been reported. Powder or capsule form is recommended. 

6. Garcinia Cambogia Extract

How it works: Garcinia Cambogia Extract is believed to inhibit an enzyme used in lipogenesis (the formation of fat). 
Effectiveness: Some animal research suggests it increases the release of serotonin in the brain, which can help suppress your appetite.
Side Effects: The most commonly reported side effects are headache, nausea, diarrhea and stomach and intestinal problems. There are also reported cases of liver toxicity associated with this product.

Stacey Pence is a registered dietitian for Nutrition Services at The Ohio State University Wexner Medical Center