Eating enough, and your periods

Running a menstrual cycle takes energy. If you are not eating enough to cover everything your body does, including exercise, growing and daily life, it can turn the cycle down to save energy. Doctors call this low energy availability. A period that gets lighter, later or goes missing can be an early sign.

Signs to notice

• Periods that get lighter, further apart or stop. The NHS says to see a GP if you miss 3 periods in a row.
• Feeling cold, tired or dizzy, or a racing heart or fainting.
• Getting ill more often, or aches and injuries that will not settle. The IOC says low energy availability can affect immunity, bone health, mood and more.
• Strict food rules, worry about eating, or exercise that feels like you cannot stop.

What helps

• Fix the cause. Experts say the heart of treatment is finding why the energy is low, then giving the body more fuel, less load, or both.
• Eat regularly, and include carbohydrates. The IOC's 2023 statement points to low carbohydrate availability as part of the problem.
• Tell someone: a GP, a parent or carer, a coach, a friend. You do not have to work it out alone.
• Ask your GP about a registered dietitian. The BDA says you can be referred by your GP.

Fasting, keto and very low-carb plans

Social media loves these for "hormone health". There is very little research on how they affect periods. A 2022 review found so few human studies of fasting and reproductive hormones that it could not draw solid conclusions. If you try a big change in how you eat and your periods change or stop, take that as your cue to stop and talk to a GP.