When British biochemist Terence Kealey launched his book on breakfast in 2017, the battle cry "Breakfast is the new smoking" made headlines around the world. Since then, there have been regular new studies into whether, when and how we should eat - or not eat - in the morning.

In the course of an endocrinology conference, a study was presented that associated an increased risk of type 2 diabetes with a late breakfast. According to this, people who have breakfast early have a better blood sugar level. Actually, the researchers examined the effects of fasting and came to their conclusions. "We found that people who started eating earlier in the day had lower blood sugar levels and lower insulin resistance, regardless of whether they restricted their food intake to less than 10 hours per day," said Marriam Ali, lead researcher at the Study, from the University of Chicago.

For the study, Ali and her team examined data from over 10,000 adults. They found that intermittent fasting, or eating for a limited time window of 10 hours or less per day, was associated with higher insulin resistance. That means people who fasted were less responsive to insulin, a hormone that regulates blood sugar. Insulin resistance is considered a risk factor in type 2 diabetes. However, these results contradict other studies. Researchers there found that fasting increases insulin sensitivity.

However, people who ate before 8:30 a.m. showed less insulin resistance. And while fasting arguably doesn't matter for blood sugar levels, an early breakfast does. People who ate before 8:30 a.m. also had lower blood sugar levels. According to Ali, the results suggest that the timing of eating has a greater impact on metabolism than previously thought.