Calories and fasting, the femLove way

Lots of women track what they eat or try intermittent fasting, usually in a separate app from the one that knows about their cycle. We've brought both into femLove, and we made a few deliberate choices along the way. Here they are.

How your calorie goal is worked out

femLove uses the Mifflin-St Jeor equation, one of the most widely used ways to estimate how much energy your body uses at rest. For women it is:

10 × weight in kg + 6.25 × height in cm − 5 × age − 161

That number is then multiplied by how active you are, from mostly sitting (× 1.2) to training hard every day (× 1.9). The result is roughly what keeps your weight steady.

If you want to lose or gain weight, femLove takes away or adds a little each day. A kilogram of body weight is roughly 7,700 kcal, so losing 0.5 kg a week means eating about 550 kcal a day less than your maintenance number. You choose the pace: 0.25, 0.5 or 0.75 kg a week.

It's an estimate, and bodies vary. If your weight changes faster or slower than planned, adjust the pace.

The limits we built in

• Never below 1,200 kcal a day. If your chosen pace would take you lower, femLove keeps the goal at 1,200 and tells you to expect slower progress. (MyFitnessPal uses the same minimum for women.)
• No weight-loss goal while you are pregnant or breastfeeding, or under 18. You'll see a maintenance number instead, with a note to check with your midwife or doctor.
• Calorie-free mode. Some people do better without numbers. Turn it on and you can still log meals, with no calories anywhere in the app. If an eating disorder is on your health record, femLove starts you in this mode, and you can change it.

Faster food logging

Start typing and femLove suggests common foods, from porridge and eggs to jollof rice, egusi and plantain, with a typical portion and its calories filled in. Change any number before you save. The list is built into the app, so what you eat is never sent to a food service.

Fasting, gently

The fasting timer works the way you'd expect: pick a goal (13, 14, 16, 18, 20 or 36 hours, or your own), start, and end whenever you like. Ending early is fine. You'll see your last seven days, your average and longest fast, and how you felt.

A few things are different:

• Before your first fast, a short read. Fasting isn't right if you are pregnant, trying to conceive, breastfeeding, under 18, have had an eating disorder, or have missing periods without a known reason. If you have diabetes, take medicine that lowers blood sugar, or have a heart condition, talk to your doctor first.
• Your cycle is in the picture. In the five days before your period and the first days of it, femLove suggests that a shorter fast, like 13 hours, may feel better. Some women find fasting harder then. femLove never changes your goal for you.
• If you feel faint, dizzy or unwell, end the fast and eat. Choose "Unwell" when you finish and femLove will say so plainly.
• Discreet notifications. When your timer is done, the lock screen says "Your timer is done." Nothing about food or fasting.

Private, like everything else

Your food goal and fasts are stored in the EU and only your account can read them. There is no setting to share them through Cycle Link. They're in your data export, and they go when you delete your account.

femLove is not medical advice. If you have a health condition or take regular medicines, talk to your doctor before changing how you eat.