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Your hormones run your weight more than calories do.

Every morning FemFast reads your cycle and hands you one plan: when to eat, when to fast, how to train.

Take the 60-second check-in See your plan on any day of your cycle

Freeno signup4.8 from 2,100+ App Store ratings

The FemFast daily dashboard: today's phase, fasting window, meals, training and supplements

Evelyn's Day 8. Yours won't look like this.

28 days in a cycle that almost no weight-loss plan accounts for

4 metabolic phases a month — most plans are written for one of them

60s to see your phase and the plan that fits it

Most women don't fail at diets. Diets fail their hormones.

Never a willpower problem. A timing problem.

You do everything right and the scale holds still.

Some weeks you have no appetite. Some weeks you can’t stop.

Your energy for training changes. Your programme doesn’t.

One month is four different bodies. FemFast plans for each one.

Day 6

Follicular

↺Drag to explore any day

DAY 6–13 OF 28

Insulin sensitivity is on your side. Your longest fast, your hardest sessions.

Fasting 16:8 — your longest window

Food Higher carb, high fibre

Training Strength and HIIT

Supplements B-complex, vitamin D, omega-3

Which phase are you in today?

Six questions. Then the fasting window, food and training that fit it.

Take the check-in

One plan, rewritten every morning.

Four things move with your phase. Here's the whole month.

Menstrual

Day 1–5

Follicular

Day 6–13

Ovulatory

Day 14–16

Luteal

Day 17–28

Fasting

12:12 — gentle

16:8 — your longest window

14:10 — moderate

12:12 — pulled back

Your longest window lands where insulin sensitivity is highest. It shortens before cravings peak.

Food

Carbs

Iron, warmth, steady carbs

Higher carb, high fibre

Protein forward, anti-inflammatory

More carbs, more salt, magnesium

Targets move with your phase. Nothing is banned.

Training

Walking, mobility, light lifts

Strength and HIIT

Heavy strength, sprints

Steady-state, moderate lifts

Build weeks two and three. Weeks one and four are for recovery.

Supplements

Magnesium, iron

B-complex, vitamin D

Zinc, vitamin C

Magnesium glycinate, B6, calcium

Omega-3 daily, all month.

What to take and when, each with its source in the app.

Ask it anything, any hour.

It already knows your phase, so you never explain yourself twice. And it's awake at 2am.

07:15 What should I eat today?

13:20 Work dinner Thursday — can I move my eating window?

18:05 How can I improve my mood?

22:40 I'm exhausted. Is this my phase, or is this me?

Ask anything. It won't diagnose — that stays your doctor's job.

Ask FemFast In app

FemFast AI assistant: it opens by naming her follicular phase, then answers what to eat today with protein suggestions

Women who stopped blaming themselves.

4.8 · 2,100+ ratings on the App Store

Exactly what I need My cycle is crazy irregular but FemFast still gives me clear steps. No other fasting app did that. Total gamechanger. Moni_ca1863 · Aug 2025 · App Store review Really nice app! I have PCOS and it’s tough finding advice that doesn’t make me feel broken. This app is gentle but also science-based. Exactly what I needed. Marilli5 · Aug 2025 · App Store review

Three findings the calorie model leaves out.

What the research shows, and how sure we are. Every recommendation in the app is sourced.

General guidance only. Your clinician stays your clinician.

Insulin sensitivity shifts weekly

Higher in week two, lower in week four. So your carbs move with the week.

Supported

Yeung et al., J Clin Endocrinol Metab, 2010

Metabolism rises before your period

A little higher, with real hunger to match. Your body is doing more work.

Supported

Benton et al., PLoS One, 2020

Long fasts cost women more

Most fasting research was run on men. Early evidence suggests women’s stress response to long fasts differs, so we keep windows shorter.

Emerging

Heilbronn et al., Obesity Research, 2005

Will this work for me?

The honest answers.

Yes — that's the case we built hardest around. Tell us roughly where you are, or that you don't know. It sharpens over the first six weeks.

Because your body does. A plan that stays flat is wrong three weeks out of four.

No. Turn it off and FemFast still times your food, training and supplements. The timing is the point.

No. Not if you're pregnant or breastfeeding, have any history of disordered eating, or take medication that needs food. FemFast asks first and won't suggest it. When in doubt, ask your clinician.

Nothing on this page is stored. In the app it builds your plan and nothing else — never sold, never shared. Delete it all in one tap.

Energy and cravings usually shift within one cycle. Weight follows over two or three.

Risk-free for five days.

Not for you? Money back in five days. No form, no questions.

3 months Try a full reset

$17.99 $6.00 / month