The obesity epidemic in the United States has brought an array of dietary supplements to help you slim down. Many of these supplements contain similar ingredients--stimulants and herbal extracts purported to assist in weight loss. Only a few ingredients have significant scientific evidence backing their weight-loss claims. In addition, some ingredients can cause side effects if taken in large quantities. Consult a doctor before using any diet supplements.
Green Tea Extract
Green tea extract is among the most popular herbal ingredients in energy and diet supplements. Green tea extract contains caffeine, which might help increase your energy levels and improve focus to help you exercise longer and burn more calories. In addition, green tea extract contains catechins, a type of antioxidant that might promote weight and fat loss. A study published in the February 2009 issue of the "Journal of Nutrition" found that 12 weeks of green tea extract supplementation increased the amount of abdominal fat burned by participants compared to caffeine. However, these results were in conjunction with exercise, so you might have to work out to have similar success.
Caffeine
Caffeine is often a main ingredient in weight-loss and diet supplements because it can increase energy levels, which might drop on low-calorie diets. In addition, caffeine might help suppress your appetite. However, research from the September 2005 issue of the journal "Psychosomatic Medicine" found that when those who were not accustomed to caffeine consumed the stimulant, their bodies secreted higher levels of cortisol. According to the women's health website Project Aware, high levels of cortisol can lead to weight gain.
Guarana
There is not much scientific evidence to promote guarana's role in weight-loss supplements although, according to the medical information website Drugs, guarana contains high levels of caffeine, which can improve your energy levels. Guarana often is used as an appetite suppressant, though there is no real scientific evidence that it works, according to the Drugs site. Guarana also can cause side effects such as restlessness, upset stomach, irregular heartbeat or diarrhea.
Conjugated Linoleic Acid
Unlike many other diet supplement ingredients, Conjugated Linoleic Acid, or CLA, is not a stimulant; it is a fatty acid. Although consuming fat to lose fat might seem like a bad idea, research suggests that CLA supplementation might be beneficial for weight and fat loss. A study published in the March 2007 issue of the "British Journal of Nutrition" found that six months of CLA supplementation, using 12 grams daily, significantly reduced fat mass compared to placebo. However, CLA does contain calories, so you should monitor your dosage carefully.
References
- "Journal of Nutrition"; Green Tea Catechin Consumption Enhances Exercise-Induced Abdominal Fat Loss in Overweight and Obese Adults; KC Maki et al; February 2009
- "Psychosomatic Medicine"; Caffeine Stimulation of Cortisol Secretion across the Waking Hours in Relation to Caffeine Intake Levels; WR Lovallo et al; September 2005
- Project Aware: Cortisol and Weight
- Drugs.com: Guarana Medical Facts
- "British Journal of Nutrition"; Six Months Supplementation with Conjugated Linoleic Acid Induces Regional-Specific Fat Mass Decreases in Overweight and Obese; JM Gaullier et al; March 2007
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