Is it safe to eat LCHF when you’re pregnant?


Is it a good idea to fast intermittently when you’re trying to become pregnant?

Get the answer to this and other questions – is it safe to eat LCHF when you’re pregnant? And can a ketogenic diet and intermittent fasting help one recover from hypothalamic amenorrhea? – in this week’s Q&A with the fertility specialist Dr. Fox:

Fasting and trying to conceive?

Hi Dr. Fox,

My husband and I have been doing a Keto diet for 3 months now, and are enjoying our weight loss progress. We have added intermittent fasting, eating 1 or 2 meals a day normally and fasting for 1 or 2 days sporadically. How does fasting affect fertility? I’ve read enough to know that I shouldn’t fast while pregnant, but what about when trying to conceive? I recently read “If you have problems with fertility and/or are trying to conceive, then consider holding off on intermittent fasting for now.”… Your advice? Would sticking with a 16:8 schedule every day help to balance out hormones instead of constantly changing it up?


Dr. Fox:

To answer your question, I think it all boils down to stress. If you are truly keto adapted, then it probably does not matter about IF or being ketogenic.

I would, however suggest that you should never go without protein even in IF episodes. In a 24-hour period, the minimum protein requirement of 1-1.5 gm/kg of ideal body weight for height should be ingested. This is not going to be more than 300 calories or so, which will still exert a significant downward pressure on weight.

I would also offer, however, that it is not about weight but about insulin levels. LCHF rapidly lowers insulin levels and improves the metabolic state. Don’t be fixated on weight but rather insulin levels that require a consistent effort at the diet. This is much more important from a fertility standpoint than absolute weight.

If you are not keto adapted, then IF will cause hypoglycemia and this “stress” will be very negative for pregnancy. If however, you are asymptomatic during IF episodes, then you are likely keto adapted and can tolerate the IF.

Best of luck.

I’m pregnant! Is it safe to continue eating an LCHF diet?

Is it safe to continue with LCHF during pregnancy? And if so, is there anything I should be doing differently?


Dr. Fox:

This is the most important time for you to be as strict as possible. The epigenetic risk to your unborn fetus is great and the adherence to LCHF will reduce the risk of stimulating the IR gene sequence in its metabolic gene expression.

The theory now is that we all have the same metabolic gene but we are individually stimulated by signals from our mother during pregnancy to either turn on insulin resistance or suppress it. LCHF will suppress this negative factor in fetal development.

Best of luck.

Also remember, in pregnancy women are extremely insulin resistant so calories in every few hours or so is important especially in the first trimester.

Can keto and intermittent fasting help me recover from hypothalamic amenorrhea?

I am 33 years old, lean (21% body fat) and athletic. I do weightlifting four times per week for one hour and I believe the hypothalamic amenorrhea was caused by several months of an intense-sports event preparation. I stopped the crazy training and caloric deficit in July.

All hormones seem fine in recent blood tests (0.5 nmol/L Testosterone, 0.8 iu/L LH level, 142 mlU/L prolactin, 7 iu/L FSH) but I haven’t had a period since April when I stopped the pill.

I’ve had PCOS plus insulin resistance since age 13 (although never overweight) but have managed to get rid of all the symptoms thanks to keto. I never had irregular periods before.

I love keto + IF (16:8 daily) it makes me feel great and I don’t count calories or restrict anymore. However everywhere I look they say you can’t fast or avoid carbs and that you need to stop training and put on considerable weight if you want to overcome hypothalamic amenorrhea. It’s so confusing! In your experience, can LCHF + IF help or worsen hypothalamic amenorrhea?

HUGE thanks Dr. Fox,

Dr. Fox:

Hypothalamic dysfunction in women is an epidemic following what I call the “exercise revolution” that began about 1980 and the dramatic change in athletics for women in U.S. schools about that time. Women now feel ashamed if they don’t engage in some high-level sport, where just a few years prior, they were not expected to be involved in sports. The latter attitude was present for the 100 million years leading up to 1980.

In addition to the dramatic increase in fertility issues it creates, low estrogen causes all the major psychiatric issues for women: PMS, migraine headaches, depression, anxiety, ADD, bipolar disorder etc. etc. This is a huge problem in our world.

As stated in your prior answer, the sensitization to stress seems to be permanent. Certainly, everything done to decrease stress brings the physiology back toward normal, but still needs some help. Almost every woman with this problem needs supplemental estrogen to fell normal.

Amenorrhea is the dramatic example but the vast majority of women suffering from this have very subtle ovulation and menstrual changes resulting in 30 – 32 day cycles, something that is seen as normal by almost all physicians including reproductive medicine physicians.

Only the amenorrheic patients are getting any press in the medical literature and they are few and far between. In the exercise world, these are the marathoners and the triathletes.

To answer this question though, keto relieves any nutritional stress that is present, i.e. hypoglycemia. Therefore you should stay the course!

More questions and answers

Questions and answers about low carb

Read all earlier questions and answers to Dr. Fox – and ask your own! – here:

Ask Dr. Fox about nutrition, low carb and fertilityy – for members (free trial available)

Videos with Dr. Fox



How to reverse PCOS with low carb

Leave a reply

Reply to comment #0 by

Older posts