A strong coffee after a poor night’s sleep is something many people feel they need in the morning. However, a new study suggests it may be better to eat something first. According to CNN, drinking coffee before eating can negatively affect blood sugar control — a risk factor for diabetes and heart disease.

“We know that nearly half of us will wake up in the morning and, before doing anything else, will drink coffee. Intuitively, the more tired we feel, the stronger the coffee,” says Professor James Betts, co-director of the Centre for Nutrition.

For their study,

researchers at the University of Bath recruited 29 healthy men and women to take part in three different overnight experiments. Participants had a normal night’s sleep, approximately from 11:00 p.m. to 7:00 a.m., and were asked to consume a sugary drink upon waking.

They then experienced a disrupted night’s sleep, where researchers woke them every hour for five minutes by sending text messages they had to respond to. After waking, they were given the same sugary drink.

On another night, participants experienced the same sleep disruption, but this time they were given a strong black coffee 30 minutes before consuming the sugary drink. The glucose drink reflected the same number of calories as a typical breakfast.

The researchers found that a disrupted night’s sleep did not worsen blood glucose and insulin responses compared to a normal night’s sleep. However, consuming strong black coffee before breakfast significantly increased the blood glucose response by about 50%.