Your body doesn’t just burn calories; it decides what kind of calories to burn. A new study from the University of Turku in Finland suggests that even small lifestyle changes, like standing up more often or taking short walks, can improve how efficiently the body uses fats and carbohydrates for energy.
The six-month study, published in the Scandinavian Journal of Medicine & Science in Sports, looked at 64 adults who were sedentary and at risk for heart disease or type 2 diabetes. One group was asked to sit an hour less per day by adding light activity, while the other group continued their usual routine. Researchers tracked movement with accelerometers to capture real-world results.
They found that participants who actually reduced their sitting by at least 30 minutes per day showed measurable improvements in metabolic flexibility, the body’s ability to shift smoothly between using fat and carbohydrate for fuel.
“A healthy body burns more fat at rest, but after meals and during high-intensity exercise, the main source of energy shifts to carbohydrates,” explained Postdoctoral Researcher Taru Garthwaite from the University of Turku. “If metabolic flexibility is impaired, blood sugar and lipid levels can rise and, instead of being used for energy production, excess fat and sugars may be directed to storage.”
That means people who spend much of their day sitting may not just burn fewer calories, they may also store more of what they eat as fat. Improving metabolic flexibility helps the body better manage blood sugar and fat metabolism after meals, key factors in long-term metabolic health.
“Reducing sedentary behavior and increasing even light daily physical activity — for example, standing up for a phone call or taking short walks — can support metabolic health and potentially help prevent lifestyle diseases in risk groups,” Garthwaite said.
The researchers note that the benefits were clearest among participants who were physically inactive or carrying excess weight. More structured exercise, about 2.5 hours of moderate activity per week, still offers greater improvements, but this study shows that even small shifts in daily habits can have meaningful metabolic effects.
This work was supported by the Research Council of Finland, Finnish Cultural Foundation, Finnish Diabetes Research Foundation, Hospital District of Southwest Finland and Juho Vainio Foundation.