Your hormones shift across four distinct phases. Your nutrition should too.
Cycle syncing is the practice of aligning what you eat, how you train, and how you live to your menstrual cycle's four hormonal phases: menstrual, follicular, ovulatory, and luteal. The term was popularised by functional nutritionist Alisa Vitti, and is grounded in the fact that your hormone levels (oestrogen, progesterone, LH, and FSH) don't stay constant across the month.
These hormonal shifts affect your metabolism, insulin sensitivity, energy levels, sleep quality, gut function, and nutrient needs. A nutrition approach that ignores this is leaving significant optimisation on the table, and it often makes the difficult days harder than they need to be.
The evidence base is growing. Studies show that resting metabolic rate increases by 100–300 kcal/day in the luteal phase. Insulin sensitivity measurably decreases pre-period. Iron needs spike during menstruation. Omega-3 fatty acids directly counter the prostaglandins driving period pain.
Cycle syncing for nutrition doesn't mean a different diet every week. It means adjusting a few key variables (calorie targets, macro ratios, and food priorities) based on where you are in your cycle. Most women notice a meaningful difference within 2–3 cycles.
What to eat in each phase of your menstrual cycle
Oestrogen and progesterone are at their lowest. Prostaglandins drive inflammation and cramps. Iron is lost through bleeding, and omega-3 is the nutrient with the most trial attention for period pain, though Cochrane rated that evidence low quality.
Oestrogen rises steadily as follicles develop. Energy, mood, and focus tend to be higher. Metabolism is slightly lower; your body is efficient. This is a good phase for higher-intensity training and more adventurous eating.
Oestrogen peaks, then LH surges to trigger ovulation. Energy and confidence are typically at their highest. Your body can handle more, and wants it. Anti-inflammatory foods support healthy ovulation.
Progesterone rises sharply. Metabolism increases by 100–300 kcal/day. Insulin sensitivity drops slightly, making carb cravings real and physiological, not weakness. Serotonin dips, driving cravings for carbs that boost it.
Cycle syncing is genuinely hard to do manually
You need to know your current cycle day. You need to know which phase that maps to. You need to know how your targets shift for that phase. And you need to log your food against adjusted targets, every day, across a 28-day cycle that isn't perfectly regular.
Most people who try cycle syncing with spreadsheets or generic apps give up within a month. Not because the approach doesn't work, but because the execution overhead is too high.
The women who stick with cycle syncing long enough to see results are typically those with the time and motivation to track meticulously. That's a small fraction of the people who would benefit from it.
The obvious solution is automation: an app that reads your cycle from Apple Health, knows your current phase, and adjusts your nutrition targets without you having to think about it. That's exactly what Oli does.
Cycle syncing nutrition, without the manual work
Oli connects to Apple Health on setup and reads your menstrual cycle data, including period start dates and cycle length history. No manual tracking required.
Based on your cycle data, Oli knows whether you're in your menstrual, follicular, ovulatory, or luteal phase today. It updates daily without any input from you.
You set a calorie and macro profile for each of the four phases, or accept the AI Target Coach's suggestion, and Oli switches between them on its own: typically higher in the luteal phase for the raised metabolic rate, lower during your period. Your daily number glides between the profiles rather than jumping.
Iron, omega-3s, and an honest read on what the period-pain research supports.
Rising energy, rising oestrogen. What to eat when you feel your best.
Peak energy, peak calorie window. What to eat to make the most of it.
Higher metabolism, real cravings. How to eat for PMS without fighting your body.
Let Oli handle the tracking part
Your phase, your targets, adjusted automatically every day.
iOS · Free to try · No card required