In my book The Anti-Anxiety Diet, I share how ketones have the ability to cross the blood-brain barrier serving to reduce oxidative stress in the brain, supporting optimal neurotransmitter signaling and directly influencing GABA, a powerful inhibitory neurotransmitter that reduces the fight-or-flight response, serving to provide a grounding anti-anxiety effect. Here, I cover why keto can lead to problematic hormone imbalances in some people and the simple (and satisfying) way you can get your body back in balance via carb cycling. In many healthy individuals, the fact that keto is a stressor is usually fine and often healthful—after all, in addition to keto, many health-promoting practices (e.g., exercise, intermittent fasting, using a sauna) are also stressors and, as such, help the body become more resilient over time. But when your allostatic load becomes too great—say, for example, you’re chronically stressed, under-sleeping, practicing intermittent fasting, and following a keto diet—your body is simply overtaxed and hormonal imbalances can result. Beyond insulin and sexual hormone production, leptin, a hormone of satiety and metabolic regulation, is affected by the ketogenic diet. Leptin—produced by fat cells and in the small intestine in response to consumption of fat—helps suppress appetite, and this is a primary reason many people on keto see a significant reduction in hunger and cravings. Leptin also has an impact on excitatory neurotransmitters in the brain, serving as one of the mechanisms by which the ketogenic diet reduces seizure activity and anxiety. Leptin can be seen in excess in obese and overweight individuals, and at high levels, leptin’s signals become resistant—which can trigger overeating. The ketogenic diet, which includes dietary consumption of fat and supports the mobilization of body fat in the production of ketones, will naturally reduce leptin levels, aiding in optimal leptin signaling in overweight individuals who were previously in a state of leptin resistance, which can help curb hunger. However, individuals who are at a low body fat percentage, or who are over-stressing the body with mental demands, calorie restriction, intermittent fasting, or too much exercise, are ramping up their allostatic load and setting themselves up for declining leptin levels—which, over time, can drive anxiety, insomnia, and hunger. And because leptin has a significant influence on the thyroid and ovaries, individuals with hypothyroidism, and menstruating women leading a high-stress lifestyle who don’t carry extra body fat, are especially susceptible to leptin imbalances when they enter ketosis. This can interfere with thyroid hormone production, throw off a woman’s cycle, and suppress hormone production. When too low, leptin requires a surge of glucose followed by insulin to tell the body it’s being adequately fed and ultimately “safe,” supporting a shift back into healthy regulatory function versus reactive survival mode. The good news: This can be accomplished by carb cycling. For the majority of your keto diet, you’ll be consuming somewhere in the range of 30 to 60 grams of total carbs per day, give or take a bit, depending on your activity levels. But when you carb cycle, you’ll be consuming an additional 45 to 60 grams of carbs per day—for a total of 75 to 120 grams of carbs—for two days of your cycle. Typically, I recommend carb cycling on days 19 and 20 of your cycle (which is five days post-ovulation), when leptin levels are naturally the lowest. This is also when your body is supposed to be making the most progesterone, but often, women who are under a lot of stress aren’t able to produce enough progesterone due to a phenomenon called pregnenolone steal, which diverts the building blocks of progesterone to produce the stress hormone cortisol. Upping your carb intake at this time helps take some of the stress off your body so you’re able to produce appropriate levels of progesterone and enjoy overall hormonal balance. It’s also best to carb cycle in the evening to support serotonin and melatonin demands, and to help your body enter a parasympathetic rest-and-digest state. I recommend trying the above approach for a few cycles and seeing how you feel. (Using a period-tracking app like Clue can be incredibly helpful in determining where you are in your cycle.) But, if it doesn’t seem to be helping, you can experiment with carb cycling on days 1 and 2 of your menstrual cycle—which is the very start of your period and the other point in your cycle when leptin levels are lowest. This can be a nice way to support your body as it undergoes the process of shedding the uterine lining. If you don’t get a period, you may follow the moon cycle, using the full moon to signify ovulation. Additionally, anyone can use carb cycling as a way to practice food freedom and schedule their “carb-ups” to correspond with social commitments or travel. If you are a postmenopausal woman or a man, simply carb cycle on the first two days of the month, or any other consecutive two-day period, and try to stay consistent. To ensure you reap these benefits, I encourage you to listen to your body for feedback on what feels right and tweak (the frequency of your carb cycling days and/or the number of carbs you consume on those days) as needed to support your body. Her Food-As-Medicine philosophy is supported by up-to-date scientific research for a functional integrative approach to healing the body. Ali is a certified diabetes educator (CDE) and renowned expert in the ketogenic diet with over a decade of clinical results using a unique whole foods approach tailored to support thyroid, adrenal and hormonal balance. Ali’s message has influenced millions through the medical community and media with television, print, and her award winning podcast, Naturally Nourished. Ali’s expertise can be accessed through her website: www.alimillerRD.com offering her blog, podcast, virtual learning, and access to her practice and supplement line Naturally Nourished.
