Clinical+Studies

=__**Research on Caffeine’s Effects on Weight Loss**__=

**Overall**
In general, caffeine studies found that the effects of caffeine on weight loss are minute in humans and do not recommend caffeine as a viable standalone weight loss strategy. However, in murine models, these effects are pronounced.

**Longitudinal Study on Caffeine and Changes in Weight Gain**
Lopez-Garcia et al. performed a 12 year longitudinal study with a subject pool initially consisting of 121,700 female health professionals between the ages 30-55, and 51,529 male health professionals between the ages 40-75. Subjects were given a questionnaire every two years based on food intake and physical status. [2]





Lopez-Garcia et al.’s findings are shown in Table 1. They depict the weight changes measured against change in median caffeine intake over the 12 year span for men and women. These findings were stratified against the factors of age, smoking status, BMI, physical activity, and alcohol consumption. Lopez-Garcia et al. found that between the extreme changes in median caffeine intake over the 12 year period (decreased the most and increased the most), weight gain in kg did not vary significantly for men or women. They found that the difference the mean weight gains were -0.40kg for men and 0.38kg for women. [2]

**Rat Study on Caffeine and Lipid Metabolism**
Kobayashi-Hattori et al. performed a 21 day study on caffeine intake in rats who were fed high fat diets. Rats were given varying percentages of caffeine (CF) and then their adipose tissues were harvested and weighed. Comparisons were made between different caffeine percentage groups as well as control groups.[3]

Kobayashi-Hattori et al.’s findings are shown in Table 2. Overall, there were significant decreases in mg/dl of total cholesterol, cholesterol esters, total lipids, serum triglycerides, free fatty acids, and hepatic triglycerides with increases in caffeine percentage. These decreases also became larger as the caffeine percentage was increased. In table 2b, findings from the same study depict that weight gain during the high fat diet period was not significantly affected by caffeine. However, significant reductions in total body fat mass and body fat percentage can be seen as caffeine percentage increases. This suggests that caffeine was responsible for the loss in mass. [3]