New Study Finds Weight Loss Does Not Improve Fertility

by Margaret Wertheim, MS RD

If anyone saw the headline in the past couple of days from Penn State that Weight Loss does not Improve Fertility, you may be wondering how this can be given we often tout our new fertility-friendly weight loss program at the Moon called FirstLine Therapy for Fertility (FLTF). Well, I'm afraid that I will have to beg to differ with the researchers' conclusions, and I'll tell you why. First here's a little background on the study:

In this study, the researchers took 29 women who were morbidly obese, which means they had a BMI over 40. They measured frequency of ovulation before and at the following time-points after gastric bypass surgery (1, 3, 6, 12, and 24 months). The researchers report no change in ovulation frequency from before to after surgery. They report ovulation frequency at about 90% before and at all time-points post-surgery.

My first problem with this study is that ovulation and fertility are not the same thing. Just because a woman is ovulating doesn't mean she can get pregnant. Of course, ovulation is necessary for pregnancy, but ovulation and fertility are in no way synonymous. The question really is can these women get pregnant and stay pregnant. We know that obesity is associated with increased insulin resistance, inflammation and may increase miscarriage and preeclampsia risk.

The researchers also report a baseline ovulation rate of 90% in these women, so if they are using ovulation as a measure of fertility these women don't sound in any way infertile to me. It seems that it would very difficult to achieve a statistically significant change in ovulation rate with weight loss when you're starting at 90%.

Finally, weight loss as a result of modifying your diet and lifestyle in a very healthy way such as we do with FLTF (including high quality protein, lots of vegetables, legumes, nuts, fruit and healthy fats) is very different from weight loss induced by gastric bypass surgery. The Roux-en-Y gastric bypass procedure inherently creates malabsorption of nutrients, and women who undergo these surgeries often need to take multiple vitamin and mineral supplements and need to be closely monitored to prevent and correct nutritional deficiencies. While weight loss is of course the goal in women who are overweight, at the Moon we work on nourishing up in order to correct any existing nutritional deficiency and ensure plenty of nutrients that are supportive of fertility and pregnancy.

I look forward to any comments or questions on this topic!

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