Consuming protein at night increases the blood sugar level in the morning for healthy people, leading to health problems such as diabetes, heart disease and obesity, say researchers.
Previous research has shown that a snack a few hours before a meal can help control blood sugar levels, which may partly explain why the first thing we eat each day (i.e. breakfast) tends to increase blood sugar more than other later meals.
"This study investigated whether waking up at night to consume some protein might keep blood sugar lower the next morning," study authors from the University of Basel in Switzerland wrote.
Insights into Controlling Blood Sugar Levels
Surprisingly, the blood sugar response to breakfast was higher when participants had consumed protein rather than plain water at 4 a.m. These unexpected findings may be informative for people trying to improve their control over blood sugar levels, the researchers said.
The research team studied 15 healthy young men and women (8 females and 7 males). The participants were woken up at 4 a.m. to drink 300 ml of a water solution, either with or without 63 grams of whey protein.
Then they went back to sleep, and at 9 a.m. they were provided with a standard amount of porridge for breakfast, with blood samples collected 2 hours after to check the blood glucose response.
Turning Protein To Sugar
According to the study, one explanation for the result is that the body does not expect or need much food to be consumed during the night and so the protein itself was turned into sugar.
This may result in the body having more carbohydrates already available upon waking such that the energy in the breakfast can less easily be used or stored, so it builds up more in the blood. "Future research will look at whether this applies to older and overweight people who tend to have more problems controlling their blood sugar levels," said study researcher Eleanor Smith.
"It would also be interesting to know to what extent our findings are due to eating at an unusual time or the type of protein consumed," Smith added. The study was presented this week at the Physiological Society's virtual early career conference called Future Physiology 2020.