Sleep and weight: why rest matters for your diet
How short sleep affects appetite, cravings and training, how much sleep adults need, and practical habits to sleep better while you work on your weight.
By the Fitlyn editorial team · Published · 3 min read
When people plan a diet, they think about food and exercise. Sleep is the third pillar that is easy to forget, and it affects both.
How much sleep do adults need?
Sleep experts recommend that adults get seven or more hours of sleep per night on a regular basis. Some people need more, especially after illness or intense training.
How short sleep affects your weight
More hunger and cravings
In sleep studies, people who are kept short of sleep tend to eat more, often several hundred extra calories a day, and much of it comes from snacks. Short sleep is linked to changes in appetite hormones and to stronger cravings for high-calorie foods.
Less energy to move
When you are tired, you naturally move less during the day and find it harder to train. That lowers the calories you burn.
Harder fat loss
In one well-known study, people on the same diet lost a similar amount of weight whether they slept more or less, but those who slept less lost more muscle and less fat.
Blood sugar
Even a few nights of restricted sleep can make the body less sensitive to insulin.
Habits that improve sleep
Keep a steady schedule
Go to bed and wake up at about the same time every day, including weekends. This is the single most effective habit for many people.
Watch caffeine
Caffeine can stay in your system for many hours. Try to have your last coffee, tea, cola or energy drink at least six to eight hours before bed.
Time your meals
A very large or spicy meal right before bed can disturb sleep. Try to finish your main meal two to three hours before sleeping. A light snack is fine if you are hungry.
Make your bedroom work for sleep
- Dark: use thick curtains or an eye mask.
- Quiet: earplugs or white noise can help.
- Cool: a slightly cool room helps most people sleep.
Light in the morning, dim at night
Get daylight soon after waking. In the evening, dim lights and put screens away 30 to 60 minutes before bed, or at least lower their brightness.
Use exercise wisely
Regular exercise improves sleep quality. If hard evening workouts keep you awake, move them earlier.
Alcohol and sleep
Alcohol may make you sleepy at first, but it disturbs sleep later in the night.
When to see a doctor
Talk to a doctor if you:
- Snore loudly, stop breathing or gasp during sleep, or wake up with headaches. These can be signs of obstructive sleep apnoea, which is more common with excess weight and is treatable.
- Have trouble falling or staying asleep for three or more nights a week for several months.
- Feel very sleepy during the day despite enough time in bed.
How Fitlyn helps
With your permission, Fitlyn can read your sleep from Health Connect or Apple Health and show it next to your readiness, food and training. The quick daily check-in lets you note sleep, mood and stress, so you can see how they affect your progress.
Sources
- Watson NF, et al. Recommended amount of sleep for a healthy adult: a joint consensus statement of the American Academy of Sleep Medicine and Sleep Research Society. Sleep, 2015.
- Nedeltcheva AV, et al. Insufficient sleep undermines dietary efforts to reduce adiposity. Annals of Internal Medicine, 2010.
- Al Khatib HK, et al. The effects of partial sleep deprivation on energy balance: a systematic review and meta-analysis. European Journal of Clinical Nutrition, 2017.
- Spiegel K, et al. Impact of sleep debt on metabolic and endocrine function. The Lancet, 1999.
