Sleep and weight loss

What the research shows

Short answer: yes, sleep matters for weight loss. Short sleep tends to raise hunger and may shift what you lose from fat toward muscle. Aim for at least 7 hours a night.

In a small study published in the Annals of Internal Medicine in 2010, people on a calorie-reduced diet lost similar weight when sleeping 5.5 or 8.5 hours. But with short sleep, the share of weight lost as fat dropped by more than half, and they felt hungrier.

Larger studies also link short sleep with higher body weight, though cause and effect run both ways.

How much sleep you need

The CDC recommends 7 or more hours a night for adults. Many people trying to lose weight fall short.

Simple ways to sleep better

• Keep the same wake-up time, even on weekends
• Get daylight in the morning
• Stop caffeine about 8 hours before bed
• Finish big meals 2 to 3 hours before sleep
• Keep your room cool, dark and quiet
• Put screens away 30 to 60 minutes before bed

How poor sleep affects hunger

Some studies link short sleep to more of the hunger hormone ghrelin and less of the fullness hormone leptin. Being tired also makes it harder to say no to snacks and easier to skip workouts.

A simple wind-down routine

1. Dim lights about an hour before bed
2. Set out tomorrow's clothes and food to clear your mind
3. Read, stretch or listen to something calm
4. Keep your phone out of reach
5. Go to bed at about the same time each night

The research in more detail

• Fat vs muscle: In the 2010 study, 10 adults each spent 2 weeks on the same reduced-calorie diet, once with 8.5 hours in bed and once with 5.5 hours. With short sleep, they lost about 0.6 kg of fat instead of about 1.4 kg, and lost more lean mass.
• Eating less with more sleep: In a 2022 trial in JAMA Internal Medicine, adults with overweight who usually slept under 6.5 hours were coached to sleep longer. They slept about 1 hour more and ate about 270 fewer calories a day over 2 weeks.
• How strong is this: These were small, short studies. They point the same way, but more research is needed on the long-term effect.

A worked example: setting your bedtime

Say you need to wake at 6:30 am. For 7.5 hours of sleep, plus about 15 to 20 minutes to fall asleep, lights out is around 10:40 pm. Start winding down at about 9:45 pm.

If that's far from your current bedtime, move it 15 minutes earlier every few nights instead of all at once.

Shift work and odd hours

• Keep your main sleep at the same time on workdays when you can
• Use blackout curtains and an eye mask for daytime sleep
• Plan meals around your shift so you're not grazing all night
• Pack protein-rich snacks so vending machines aren't your only option

When to talk to your doctor

See a clinician if you have trouble sleeping most nights for 3 months or more, loud snoring with pauses in breathing, restless legs at night, or low mood that won't lift. Ask before using sleep aids, since some can affect weight, mood or breathing. Stress can play a part too; see stress and weight loss and why can't I lose weight.

Food, drinks and sleep

• Caffeine: it can linger for many hours, so a late latte may cut into deep sleep even if you fall asleep fine.
• Alcohol: it may help you doze off, but it tends to disrupt sleep later in the night.
• Big late meals: they can cause reflux and restless sleep, especially on a GLP-1 medicine.
• Late-night snacking: tiredness makes it harder to stop, so a planned evening snack can help.

Sleep and exercise

Regular activity tends to help people fall asleep faster and sleep more deeply. Morning or afternoon walks also give you daylight, which helps set your body clock. Very hard workouts right before bed keep some people awake, so try finishing intense sessions a few hours before sleep.

Sleep apnea and weight

Loud snoring, gasping at night and daytime sleepiness can be signs of obstructive sleep apnea, which is common with higher body weight. Treatment can improve sleep, energy and health. Zepbound is approved for moderate to severe sleep apnea in adults with obesity. See GLP-1s and sleep apnea.