Why Dieting Can Make It Hard to Sleep
How Eating Less Affects Your Body
Cause:
When you cut back on food too much, your body notices — and not in a good way. Dieting, especially with low calories, can cause stress and hunger that keep your brain wide awake. For example, strict diets raise cortisol — the body’s main stress hormone. Cortisol acts like a natural energy booster, making it harder to relax or fall asleep.
Also, dieting lowers leptin (a hormone that helps you feel full) and increases ghrelin (the “hunger hormone”). Ghrelin activates parts of your brain that keep you awake. In simple terms, your brain acts like you’re hungry and searching for food, so it stays alert at night.
What You Can Do:
- Light evening snack: Eat something small with protein or fiber, like Greek yogurt with berries or a few nuts. It helps reduce hunger without adding lots of calories.
- Lower stress hormones: Try calming activities before bed — deep breathing, gentle yoga, or a relaxing book. A warm bath can also help you unwind.
- Adjust your meals: Even if you’re eating fewer calories, include healthy fats (like avocado or olive oil) and complex carbs (like oatmeal or sweet potato) at dinner. These foods can help your body feel safe and reduce stress.
- Skip late caffeine: Avoid coffee, energy drinks, or even green tea later in the day. Instead, try herbal teas like chamomile or peppermint.
Brain Chemicals and Low-Carb Diets
How Food Affects Your Sleep Hormones
Cause:
Your brain needs certain nutrients to make sleep-friendly chemicals like serotonin and melatonin. Carbs help the amino acid tryptophan reach your brain, where it turns into these calming chemicals. On low-carb diets or when fasting, this process doesn’t work as well. You may not make enough melatonin, and sleep becomes harder. One study found that people who ate a high-carb dinner fell asleep faster than those who ate low-carb meals.
What You Can Do:
- Best bedtime snack: About 1–2 hours before bed, have a small snack with both complex carbs and protein. Try a banana with peanut butter or whole-grain crackers with cheese. This helps boost sleep chemicals.
- Eat sleep-friendly foods: At dinner, include foods rich in tryptophan like milk, yogurt, chicken, turkey, or whole grains.
- Supplements (if needed): If you’re on a very strict diet, a low-dose melatonin (2–5 mg) might help. Magnesium (200–400 mg) or herbal aids like valerian root can calm your nerves. Always follow directions and check with your doctor.
- Check your electrolytes: Very low-carb diets can cause you to lose salt and potassium. This may lead to restless legs or fast heartbeats at night. Add a pinch of salt to water or eat potassium-rich foods like spinach or avocado.
- Stay mentally calm: Avoid late-night TV, intense video games, or work emails. Instead, dim the lights and do something relaxing like reading or breathing exercises before bed. This helps melatonin production.
Body Temperature and Metabolism
How Dieting Changes Your Body Heat
Cause:
When you’re eating a lot less, your body slows down to save energy. This also lowers your core body temperature. Normally, a slight temperature drop at night helps you sleep. But if your body gets too cold, it can wake you up or make sleep uncomfortable.
What You Can Do:
- Keep your bedroom warm enough: Set your room between 65–70°F (18–21°C). If you feel cold, use extra blankets or wear socks to bed.
- Warm up before bed: A warm bath or shower about an hour before bedtime raises your body temperature. As it drops again, you’ll start feeling sleepy.
- Use layered bedding: Try a cotton sheet and a light wool blanket. These keep you warm but let air through so you don’t overheat.
- Stay gently active: Light exercise like stretching or walking during the day helps your body regulate temperature. Avoid hard workouts late at night — they may keep you up.
Blood Sugar Drops and Missing Nutrients
Why Low Blood Sugar Wakes You Up
Cause:
Eating too little can cause your blood sugar to dip — especially at night. When blood sugar falls, your body responds by releasing cortisol and adrenaline to bring it back up. This can wake you from sleep. Also, strict diets might not give you enough vitamins or minerals, like magnesium or B-complex, which help keep your nerves calm.
What You Can Do:
- Avoid going to bed too hungry: If it’s been hours since dinner, eat a tiny snack like apple slices with peanut butter or a slice of cheese. A bit of protein and carbs can keep your blood sugar stable.
- Add nutrients: If your food intake is low, a multivitamin or extra supplements (like magnesium or B vitamins) can help fill any gaps.
- Stay hydrated: Drink enough water throughout the day. Dehydration raises stress hormones and makes sleep lighter. But don’t drink too much right before bed or you’ll be up for bathroom trips.
Build a Sleep-Friendly Routine
Simple Habits That Improve Sleep
Even if you’re dieting, good sleep habits can help a lot. Make your bedroom a peaceful place: cool, quiet, and dark. Try to stick to a regular bedtime and wake-up schedule. Turn off screens — like phones and TVs — an hour before sleep. The blue light tricks your brain into thinking it’s still daytime, which lowers melatonin.
What You Can Do:
- Be consistent: Go to bed and wake up at the same time every day, even on weekends.
- Wind down: About 30 minutes before sleep, dim the lights and stop using devices. Use this quiet time to calm your mind.
- Cut screen time: Use blue-light filters on screens or avoid them for 30–60 minutes before bed to protect melatonin levels.
- Make your bed cozy: Use a supportive pillow and mattress. If stress is keeping you up, try writing down your thoughts to clear your mind before bed.
- Get help if needed: If your sleep problems continue and you can’t increase your food intake, talk to a doctor or dietitian. Extreme calorie cuts may need professional help.
Final Thoughts
Calorie deficit insomnia is real. Eating too little can affect your sleep in many ways — by raising stress hormones, lowering sleep chemicals, cooling your body too much, or causing blood sugar dips. But you can take steps to sleep better even while dieting.
With small changes — like eating a light snack, calming your mind, and keeping warm — you can sleep more soundly and stick to your health goals.