Caffeine

  • Author:
    Betty Kovacs, MS, RD

    Betty is a Registered Dietitian who earned her B.S. degree in Food and Nutrition from Marymount College of Fordham University and her M.S. degree in Clinical Nutrition from New York University. She is the Co-Director and Director of nutrition for the New York Obesity Research Center Weight Loss Program.

  • Medical Editor: Melissa Conrad Stöppler, MD
    Melissa Conrad Stöppler, MD

    Melissa Conrad Stöppler, MD

    Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

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Does caffeine help with weight loss?

The weight-loss industry is estimated to be a $50 billion a year industry. Many people are looking for a way to get their piece of the money-making pie without a lot of credibility behind what they are promoting. The supplement industry is constantly promoting a new product to enhance weight loss by increasing satiety or burning fat. The claims are convincing, but the research backing many products is often lacking. To make matters worse, supplements often contain combinations of ingredients in the hopes of enhancing each one's effect without safety or efficacy tests. Caffeine is one of the ingredients now being included in many of the weight-loss supplements. It's added for its energy enhancement, appetite suppressant, and "fat-burning" properties.

The scientific evidence about caffeine as a weight-control agent is mixed. In a study done to monitor the impact of a green tea-caffeine combination on weight loss and maintenance, participants were divided into those who consume low levels of caffeine (<300 mg/day) and high-caffeine consumers (>300 mg/day). Weight loss was significantly higher in the high-caffeine consumption group, but weight maintenance was higher in the low-caffeine consumption group. The conclusion was that the caffeine was related to greater weight loss, higher thermogenesis, and fat oxidation, while the tea was responsible for the greater weight maintenance. Other studies have stated that caffeine actually contributes to weight gain by increasing stress hormones. It appears that caffeine's role in weight loss is as inconclusive as the efficacy of the majority of weight-loss supplements on the market.

Is caffeine safe during pregnancy?

There is no disputing the importance of proper nutrition during pregnancy. There is some dispute about the safety of caffeine during this time. One concern is that caffeine may lead to miscarriages. In a study following 431 pregnant women, no relationship between caffeine consumption up to 300 mg/day and adverse pregnancy outcomes was found. Another study examined the relationship between caffeine consumption and spontaneous abortions in over 5,000 women and found no association. A recent study found that caffeine can reach the follicular fluid of the ovaries. It also found that an increase in coffee consumption was associated with an increased number of aborted pregnancies.

On the other side, research has also shown no clear relationship between caffeine intake and fertility and birth defects. Even with this evidence, everyone agrees that there is a limit for how much caffeine can be consumed during pregnancy. The majority of the subjects in the studies were consuming small to moderate amounts of caffeine. It is difficult to accurately test the effects of very high intakes of caffeine without risking the health of the mother and child.. The American College of Obstetricians and Gynecologists recommends a caffeine limit of the equivalent of one to two cups of coffee per day during pregnancy.

Medically Reviewed by a Doctor on 2/18/2015
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