Sara Gottfried MD is a board-certified physician who graduated from Harvard and MIT. She practices evidence-based integrative, precision, and functional medicine and is Clinical Assistant Professor in the Department of Integrative Medicine and Nutritional Sciences at Thomas Jefferson University.

Interviews with Dr. Sarah on her last three New York Times bestselling books can all be explored here on The Chalkboard. And in her latest book, Women, Food and Hormones Sarah really dives in on what women should know about going keto. Her insights and personal perspective are compelling…

5 Things That Every Woman Needs to Know About Keto

I am convinced that many diet plans fail because they are designed by men for men, and not for women’s complex hormonal needs. When it comes to the popular ketogenic diet, nothing could be more true.

Diagnosed with prediabetes back in 2015, I decided to try this low-carb, high-fat diet to help me achieve metabolic health and lose weight. I tried keto twice and failed; in fact, I even ended up gaining weight.

After seeing female patients in my practice with a similar experience, I decided I had to investigate why keto was not working for women. The result is my new book, Women, Food, and Hormones which presents a modified-ketogenic diet that honors female biology.

If you are thinking of going keto or you tried it before and it didn’t work for you, here are five things that women need to know about keto.

“Hormones influence weight.”

I’m a hormone expert and for decades I have been educating women on how hormones influence weight loss. The eat less/move more approach for women simply does not work because it doesn’t take into account the effect that hormones such as estrogen, thyroid and cortisol have on weight and fat gain.

Women have more hormone problems than men do. Our hormone levels fluctuate monthly during the years of monthly menstrual cycles. Additionally, we experience major hormonal shifts at the significant transitional phases of our lives including pregnancy, postpartum, perimenopause and the menopausal years.

These transitions lead us to be more vulnerable to hormone imbalances. Women need a fat loss plan that keeps women’s hormones in balance otherwise they find their weight loss attempts are in vain and they end up blaming themselves for losing a battle their bodies weren’t equipped to fight.

The ketogenic diet influences hormones. In my clinical experience, I see three main hormones that keto has the potential to adversely affect in women: cortisol, thyroid, and estrogen.

Cortisol | In general, women’s stress levels are higher overall compared to men. The classic keto diet can add an extra burden to the stress response by not providing an adequate amount of carbs.

Carbs help mitigate the stress response so for many women, the low carb nature of keto can lead to an increase in cortisol levels. In turn, this can derail weight loss by causing the body to store rather than dump fat.

Thyroid | A diet low in carbs can negatively impact the thyroid. Carb restriction can raise reverse T3 (rT3). One of the common issues in patients on a ketogenic diet is that they may have increased rT3. This is one of the biomarkers that I check with patients who tell me they have tried keto and it didn’t work for them.

Reverse T3 is an inactive metabolite of T4 and provides a mechanism to slow down metabolism in order to save energy. It provides a feedback system to keep you in balance under normal conditions. However, if your body is stressed or on a calorie-restricted diet, a signal is sent to change the ratio, and you produce more reverse T3.

Estrogen | Estrogen may get out of balance in people who eat a “lazy” keto diet, like fast food burgers wrapped in lettuce with bacon on top without sufficient vegetables to feed good microbes in the gut.

The Detox + Digestion Component

Healthy estrogen balance relies on a healthy ecosystem of microbes. People who eat more animal products, like meat and cheese, but skimp on vegetables risk a rise in the levels of misbehaving members of the estrogen family.

Most women need to improve their detox pathways in order to burn fat successfully. With my third, and finally successful, attempt at keto, I made sure to include a detox component to ensure I was getting the vegetable-based carbs that my body and gut needed.

Most of my patients have sluggish detox and digestion. That’s why my program starts with detoxification, to augment what your body is doing already but may not be sufficient after age 35.

Each day, you need cruciferous vegetables like broccoli, cauliflower, and Brussel sprouts; allium vegetables that help to mop up toxins like onions, garlic, and leeks by helping you make glutathione; and methylating vegetables like dark green leafy greens to inactivate excess estrogens.

At least one bowel movement a day is essential for maintaining the detoxification pathways in the liver that help to excrete excess estrogen. To poop daily, women need an adequate amount of fiber, something that often gets left out with the classic keto that excludes sufficient vegetables.

Further, I recommend getting off of alcohol for a minimum of four weeks. Alcohol goes to the front of the line for liver detoxification, and limits fat burning.

When it comes to insulin and the risk of diabetes, men and women are different. Overall, women are more sensitive to the hormone insulin, at least until the peri- and menopausal years. As women get older, their cells become less sensitive to insulin which means they need more and more insulin to lower blood glucose. A continued and consistent rise in insulin levels leads to insulin block, commonly known as insulin resistance. Insulin is the main hormone involved in weight gain and encourages the body to store more fat. Thus, when following a ketogenic diet, women need to find their own personal carb limit that is not too low that it triggers the hormone problems described above, yet still low enough to reduce insulin resistance that hinders fat loss.

Get Dr. Sarah’s book, Women Food and Hormones A 4 Week Plan to Achieve Hormonal Balance Lose Weight and Feel Like Yourself Again to learn more!