Morning or Evening? What’s the best time to work out if you want to lose weight?

There’s no love like self-love. But losing weight is about doing it right and now scientists say they might have discovered the perfect time of the day to exercise. According to a new study, when you exercise matters. In the morning, people tend to burn more fat than at other times of the day, it suggests.

The study by researchers at Sweden’s Karolinska Institute and the University of Copenhagen was based on mice but scientists say the results “could prove of value” to humans. The researchers studied biological processes in mice made to run either in the morning or evening. They found that mice have a higher fat metabolism when exercising at an early active phase in their daily cycle than in an early rest phase. The early active phase corresponds to the morning when it comes to humans.

One group of rodents ran on a treadmill early in the morning while the others later in the evening. Their blood samples were examined along with the brain, heart, muscle, and liver and the impact of the exercise adipose tissue known as the body fat. Scientists looked at which genes were active in adipose tissue and discovered those involved with boosting the metabolism were more abundant in the morning slot – regardless of how much food the mice ate, according to a report in Independent.

They found that the earlier bout of exercise increased the expression of genes involved in breaking down fat by producing heat and mitochondria. This indicates a higher metabolic rate. Physical activity at different times of the day can affect the body in different ways. The biological processes depend on the circadian rhythms of the cells, the natural cycle of changes in our bodies over 24 hours, and they work differently in the morning and the evening.

Scientists say that the study suggests that there is a likelihood that humans might also see more fat loss if they work out in the morning as compared to late in the evening. “Our results suggest that late morning exercise could be more effective than late evening exercise in terms of boosting the metabolism and the burning of fat, and if this is the case, they could prove of value to people who are overweight,” said Professor Juleen Zierath of the Karolinska Institute.

According to researchers, physical exertion earlier in the day increased the expression of genes involved in breaking down fat by producing heat and mitochondria, indicating a higher metabolic rate. This bodily process, which turns food into energy for breathing, thinking and moving, dictates how many calories are burnt per day. So those with a higher metabolism use up more calories and are more likely to lose weight, according to a report in Daily Mail.

“The right timing seems to be important to the body’s energy balance and to improving the health benefits of exercise, but more studies are needed to draw any reliable conclusions about the relevance of our findings to humans,” Prof Zierath clarified. However, scientists hope that the results of the study will help in devising more effective exercise plans which are timed to the body clock, especially for patients with Type 2 diabetes and obesity.

Researchers say that the study only looked at running and the results might wary for other types of exercises. While mice are long-established for studying human physiology and metabolism, the comparison is limited by the fact that the animals are nocturnal.  “Despite these limitations, we believe that the results are of potential relevance to humans because many aspects of basic physiology are shared between mice and men,” Prof Zierath said.

The researchers now plan to investigate if similar exercise responses occur in humans. A study published in 2019 has suggested that skipping breakfast before a morning workout leads to great weight loss. According to researchers at the University of Bath, those who did not eat before working out consumed less food throughout the day.

Early morning insulin levels are lower since having fasted overnight. This pushes the body to tap into its fat reserves for fuel rather than merely targeting recently ingested calories, according to a report in Independent.