If you have read my post on circadian rhythm you will know by now that our body works on an internal clock wherein we naturally feel active during the day and sleepy at night. A very important aspect of this is melatonin which is the sleep hormone. Now, in addition to regulating circadian rhythm melatonin is also known to influence glucose metabolism.

For better context, let us first understand the co-relation between insulin and melatonin. When melatonin levels increase around night time indicating bedtime for the body, one of the essential functions that go into recovery/snooze mode are insulin production. In the sense, beta cells of pancreas which produce insulin are allowed to recover from their day long work of digesting glucose in your blood. On the other side of this, when melatonin levels drop in the morning time, insulin production has known to get  activated.

If you have read my very first post on how sleep affects hunger, you will already know that having a late dinner or a late night snack disturbs your sleep. Studies say that the co-relation between insulin and melatonin might be the reason for this. During night time, with increase in melatonin production your body naturally enters a ‘fasting mode’ wherein insulin secretion is temporarily suppressed. Hence your body’s glucose tolerance (ability to digest glucose) is reduced. Having food late in the night disrupts this activity by forcing your body to digest the food consumed. Thus when insulin production is activated for digestion, melatonin levels automatically go down. So when you do go to sleep, it sets in much later than usual and is disturbed.

That one snack you thought you needed late at night because you felt hungry might actually be the primary cause of your disturbed sleep and also weight gain. By having food late in the night you are not giving insulin the rest it needs from all the work it does throughout the day. Your sleep is also hampered due to reduction in melatonin. So, avoid having a late dinner; do not snack at night and have warm water if you feel hungry at odd times. In the long run, you will sleep better and your insulin function will also be better during the day!