Key takeaways
- Metabolism is the sum of all the chemical processes that turn food into energy.
- Resting metabolism accounts for roughly 60–70% of the calories most people burn each day.
- A 2021 study in Science found metabolism stays fairly stable from age 20 to 60.
- Muscle, daily movement (NEAT), protein and sleep are the biggest levers you control.
Metabolism is the set of chemical processes your body uses to convert food and drink into energy. Even at rest, you need energy to breathe, pump blood, repair cells and keep your brain running. Understanding where those calories go makes it easier to support a healthy weight.
Where Your Daily Calories Go
Your total daily energy expenditure has three main parts.
- Basal metabolic rate (BMR): the energy needed to keep you alive at rest. For most people it accounts for roughly 60% to 70% of daily calorie burn.
- Thermic effect of food: the energy used to digest and process meals, about 10% of the total. Protein has the highest thermic effect of any macronutrient.
- Physical activity: structured exercise plus non-exercise activity thermogenesis (NEAT), such as walking, standing, cleaning and fidgeting. This is the most variable part and can differ by hundreds of calories a day between people.
Does Metabolism Really Slow Down With Age?
Not as early as most people think. A landmark 2021 study in Science, led by Herman Pontzer and using data from more than 6,400 people aged 8 days to 95 years, found that metabolism, adjusted for body size, stays remarkably stable between about 20 and 60. It begins to decline only after 60, by roughly 0.7% per year.
So why does weight creep up in midlife? The main culprits are usually gradual muscle loss, less daily movement, more stress, poorer sleep and changes in eating patterns, all of which you can influence.
Muscle is metabolically active tissue. Losing muscle through inactivity lowers the calories you burn at rest, while strength training helps preserve it.
Natural Ways to Support Your Metabolism
Build and keep muscle
Strength training two or more days a week, as recommended by U.S. physical activity guidelines, helps maintain lean mass as you age.
Move more all day
Take the stairs, walk during calls and stand up every 30 to 60 minutes. Small bursts of NEAT add up over a week.
Eat enough protein
Protein takes more energy to digest and helps you feel full. Include a protein source at every meal.
Prioritize sleep
Short sleep disrupts hunger hormones and makes it harder to stay active, which works against your metabolism.
Where Supplements Fit
Supplements work best as support for these habits. Ingredients such as green tea catechins and caffeine have been studied for their modest effect on energy expenditure, and chromium is popular for supporting balanced blood sugar. If you take medication or are sensitive to caffeine, check with your doctor first.
Want simple daily support to go with these habits?
Learn About ChocotideSources
- Pontzer et al., “Daily energy expenditure through the human life course,” Science, 2021.
- Mayo Clinic, “Metabolism and weight loss: How you burn calories.”
- Hursel et al., “The effects of green tea on weight loss and weight maintenance: a meta-analysis,” International Journal of Obesity, 2009.
- U.S. Department of Health and Human Services, Physical Activity Guidelines for Americans, 2nd edition.
This article is for general educational purposes and summarizes publicly available information. It is not medical advice and does not describe the effects of any specific product.