If you thought your birth control was to blame for recent weight gain, it may be time to reconsider. According to research conducted at the Oregon National Primate Research Center at Oregon Health & Science University, the commonly held belief that oral contraceptives cause weight gain appears to be more fiction than fact. And in those who are obese, the pill may actually cause weight loss.
Researchers studied a group of rhesus macaque monkeys, which were used in this study because their reproductive system is nearly identical to humans and their diet can be better controlled and measured, for eight months. At the start of the study, half of the monkeys were obese and half were at a normal weight. All of the animals received oral contraceptives while researchers tracked their weight, food intake, activity levels, body fat and lean muscle mass.
What did they find? By the end of the eight-month period, the normal weight monkeys stayed at the same weight, while the obese monkeys lost an average of 8.5 percent of weight, dropped 12 percent body fat and increased their metabolic rate. Researchers say that no changes were seen in the monkeys’ food intake, activity or lean muscle mass for either group. The results of the study are published online and will appear in next month’s edition of the journal Human Reproduction.
A few caveats about the study: Despite having similar reproductive systems, monkeys are obviously not people, so while results suggest that the pill doesn’t lead to weight gain, researchers are totally sure. Also, the research was funded by the Society for Family Planning, which funds scientific research that can help strengthen family planning policies, services and programs, according to its website. Lastly, there are a number of different oral contraceptives on the market today, so it’s hard to generalize all brands’ effect on weight.
What do you think about this study? Did you gain weight after taking birth control? Did you lose weight? Tell us about it in the comments!