Exercising at night may help offset the consequences of eating greasy food, small study suggests

• Men on high-fat diets might benefit more from exercising in the evening, new research suggests.
• Night workouts were associated with lower cholesterol and better blood sugar control than morning sessions.
• However, more research is needed to see if this applies beyond this small study.

Evenings may be the best time to exercise for men looking to offset the consequences of greasy food, according to a study published May 19 in Diabetologia.

New evidence suggests working out later in the day is linked to better blood sugar control than morning workouts among men with obesity on a high-fat diet.

Researchers from the Norwegian University of Science and Technology and Australian Catholic University studied 24 Australian men with obesity, who did not exercise much, as they consumed a low-carb, high-fat diet for 11 days.

After five days on the diet, one third of the group starting to exercise in the morning once a day. Another third exercised in the evening. The rest didn't exercise at all.

The men in both exercise groups had improved cardiovascular fitness and blood sugar control after their meals and snacks, compared to the control group. However, the evening exercise group had a slight advantage when it came to blood sugar levels at night as well as levels of LDL or "bad" cholesterol.

The researchers say these findings suggest evening exercise might be uniquely helpful for metabolizing fats and sugars in a greasy diet.

Evening workouts may offset side effects of high-fat food

The researchers were trying to assess how exercise timing might affect the men's metabolism and blood sugar control in response to a high-fat diet.

In the first five days of the diet, everyone's levels of LDL cholesterol increased. This type of cholesterol is sometimes called "bad" cholesterol because it's linked to higher risk of heart attack and stroke.

Once participants started working out, though, men who exercised in the evening saw their LDL cholesterol levels drop back down, in addition to blood sugar improvements. In contrast, participants who worked out in the morning or not at all retained their elevated cholesterol levels.

It's not clear why this is the case. One explanation, the researchers suggested, is that men who woke up early to exercise may have missed out on sleep to do so. (Research has shown lack of a sleep can disrupt metabolism.)

Exercise timing matters, but more research is needed

Previous research has shown that the timing of your workouts makes a difference: it can affect your performance, as well as the health benefits of exercise, including blood sugar control, mood, and weight loss.

But more research is needed to see whether the findings of this latest study might apply to a broader population.

The number of participants was small, and it's not clear if the results would hold true for women or men with an average BMI. The study also provided pre-packaged meals to the men, with carefully controlled calories and macronutrients, so results might vary in a real-world setting.