This is the case: Patient in late 30s referred for me to help with weight loss. Has struggled with obesity for many years, trying multiple diets. Also struggles with falling pregnant and has failed attempts with IVF. Our initial plan of attack was Paleo template. She was very responsive to removing inflammatory foods from her diet. She has also cut back from her total carbohydrate intake to 85 g a day, has recently taken an interest in keto, and has reduced carbohydrates to below 30 g a day, and she feels amazing. My concern is will this be detrimental for her fertility? We’re trying and juggling trying to help her get the weight off but also not compromising her ability to fall pregnant.

Chris: It is a little tricky in this situation because part of the difficulty conceiving could be related to insulin resistance and poor blood sugar control and everything else that could go along with that. One strategy here would be to use keto as a way of getting as healthy as possible for several months. She is in her late 30s, so I imaging she’s a little bit feeling some pressure in terms of time, but certainly it’s true that the healthier the body is when entering pregnancy, first of all, the most more likely she’ll conceive, and then the more likely it’ll be that she’ll have a healthy pregnancy and carry a baby to full term and have a healthy delivery. When I work with patients, I usually say, especially with patients who are eager to get pregnant and at the point in their life where their window it is getting a little bit smaller, late 30s like these days I see that there’s still a few years left for sure. I just ask them. I say, “Being as healthy as possible really benefit you and your future baby. I know you’re feeling probably some anxiousness around timing. What do you think about spending the next six months or whatever time period you feel that is appropriate on just getting healthy as you can, which will increase your chances of getting pregnant and having a successful pregnancy?” Usually, most women see the logic in that and are willing to do that, and then once she is pregnant, I would not recommend a keto diet. A lower carb diet can still be safe in that situation. Back up to 85 to 100 g a day I think would be more reasonable, but keto is typically not recommended in pregnancy. Fortunately, if she’s already had six months of doing keto and is feeling a lot better, just transitioning back up lower carb from keto will probably not have a significant adverse effect.