The Cut-off Time: Why You Should Stop Eating at 7pm
When you eat matters almost as much as what you eat. Late-night calories are processed differently than daytime calories due to circadian biology.
You track macros perfectly. Hit your protein. Manage your calories. But you eat dinner at 9pm, snack at 10pm, and finish with something sweet at 11pm before bed. Then you wonder why the scale will not move.
Calories are not just calories. When you consume them matters. Your body processes food differently depending on the time of day, and eating late works against your physiology.
The Mechanism
Your circadian rhythm governs more than sleep. It regulates insulin sensitivity, metabolic rate, and digestive enzyme production. These functions peak during daylight hours and decline as evening approaches.
Insulin sensitivity is highest in the morning and decreases throughout the day. The same meal eaten at 8am causes a smaller blood sugar and insulin spike than if eaten at 8pm. Higher insulin responses promote fat storage and inhibit fat oxidation.
Your digestive system also follows circadian patterns. Stomach acid production, enzyme secretion, and gut motility are optimized for daytime eating. Late-night food sits in your system longer, digests less completely, and can disrupt sleep quality.
Core body temperature naturally drops in the evening to facilitate sleep. Eating raises core temperature through the thermic effect of food. Late meals fight against your body's attempt to cool down for rest, impairing sleep onset and sleep quality.
Growth hormone release peaks during early sleep. Food intake, especially carbohydrates, blunts growth hormone secretion. Eating close to bedtime reduces the anabolic hormone pulse you should be getting during the first sleep cycles.
Leptin and ghrelin, the hormones regulating hunger and satiety, follow circadian patterns too. Late-night eating disrupts these rhythms, often leading to increased hunger the next day and perpetuating a cycle of poor timing.
The Protocol
1. **Set a hard cutoff**: Choose a time 3-4 hours before bed and stop eating then. If you sleep at 11pm, stop eating by 7pm. Adjust based on your schedule.
2. **Front-load your calories**: Eat your largest meal at breakfast or lunch. Dinner should be the smallest meal, not the largest. This matches your metabolic capacity.
3. **Close the kitchen**: Physical cues help. After your cutoff time, the kitchen is closed. No browsing the fridge, no snacking while watching TV.
4. **Handle hunger with non-caloric options**: If hunger strikes after cutoff, herbal tea, sparkling water, or bone broth can help without disrupting the fast.
5. **Eat enough earlier**: Late-night hunger often results from inadequate eating during the day. If you consistently want to eat at night, add calories to breakfast and lunch.
6. **Make dinner protein and vegetable heavy**: Save most of your carbohydrates for earlier in the day when insulin sensitivity is higher. Dinner should emphasize protein and fiber.
7. **Allow occasional flexibility**: Social events and life happen. Missing your cutoff sometimes is not a disaster. The goal is consistency, not perfection.
The simplest diet intervention might be timing, not content. If you are already eating well but eating late, shifting your intake earlier could be the change that finally moves the needle. Same calories, different clock, different results.