Would you eat earlier to improve your blood sugar control?

Adapted from Diabetes in Control Sept 18 2021: Effects of earlier dinner times on glycaemic control by Andy Dao, Pharm D candidate, University of South Florida.

Growing up you may have heard from your family that eating close to bedtime isn’t a good idea. Eating later has indeed been shown to cause weight gain and metabolic dysfunction. Type 2 diabetes develops 10% more commonly in those who work shifts for instance. It is though that hormonal disruption of the circadian rhythm is the problem.

A recent study looked at how blood sugars were affected by eating earlier than 6pm or after 9pm over the whole 24 hour day. Adults over 20 wore blood sugar monitors over three days in this experiment. They were assigned to have their last meal of the day by 6pm or after 9pm. They had to eat or drink nothing but water after this meal. They were given identical meals three times a day. How they felt, what exercise they took and how well they slept were all assessed.

12 subjects completed the tests. Each group were of comparable height, weight and BMI.

There were significant reductions in blood sugar levels in the early diners in mean blood sugars throughout the whole day, night and early morning. Post prandial levels were also better in the evening for the early diners compared to the late diners but not for breakfast and lunch post prandial levels which were the same regardless of the evening mealtime.

The early diners did report more hunger and capacity to eat in the evenings than the later diners. There was no difference in sleep or physical activity.

So, if you do eat earlier, you can expect improved blood sugars all day long, and perhaps less likelihood of getting diabetes. The downside is more evening hunger. This study was done in healthy non-diabetic people and it would be interesting to see what the results in diabetic subjects would show.

Comment: Sitting down at 5 to 5.30 pm just wouldn’t work well for me, yet this is what we did in my childhood, and we didn’t eat snacks in front of the television after this. In my own house we have dinner at 7.30pm. This however is because I didn’t usually get home before 6.30 pm or even 7pm for many years so an earlier mealtime was not possible for me. I also tend to watch television from 8 pm for about 40 minutes or so before bath and bed. I couldn’t abide eating after 9pm as a regular thing, yet this is very common in Italy. I do think that I would be reaching for the oatcakes and cheese or more if I was in front of the television having eaten at 6pm.