The Biggest Contributors to Metabolism

When people talk about metabolism, they often imagine it’s something you’re born with — either “fast” or “slow.” But while some parts of metabolism are fixed, others are surprisingly flexible. With the right strategies, you can make meaningful changes. Your basal metabolic rate (BMR) is the foundation of your metabolism. It represents the energy your body needs to carry out essential life functions at rest — things like breathing, circulating blood, repairing cells, and keeping your organs running. When it comes to weight loss, BMR matters because it sets the baseline for how many calories your body burns without you even thinking about it. The higher your BMR, the more energy you burn at rest, which can make it easier to create the calorie deficit needed for fat loss.

BMR accounts for about 60–70% of your total daily energy use. Much of your BMR is determined by vital organs like your brain (~20%), liver (~20%), and your heart and kidneys (~15–20% combined). Other tissues (fat, skin, intestines, etc.) contribute to another ~20%. These organs are incredibly calorie-hungry but fixed — you can’t “train” your liver or brain to burn more.

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Beyond BMR: Movement, Food, and Adaptation

The rest of your daily energy use comes from a mix of lifestyle-driven factors:

• Physical activity (15–30%): This includes Exercise Activity Thermogenesis (EAT) or calories burned from structured exercise like running, lifting weights, or cycling as well as Non-Exercise Activity Thermogenesis (NEAT) or calories burned from everything else you do in daily life — walking around, climbing stairs, doing chores, even fidgeting.
• Thermic Effect of Food (TEF ~10%): Digesting food itself burns energy. Protein has the highest thermic effect (20–30% of its calories burned in digestion), followed by fiber (10–15%). Carbs contribute ~5–10%, and fat the least (~0–3%). Diets higher in protein and fiber not only raise TEF but also support muscle preservation and satiety (or fullness with meals).
• Adaptive Thermogenesis (up to 10%): This is your body’s adjustment system. Restrict calories too much, and metabolism slows to conserve energy; overfeed, and it burns a little more. Stress, sleep, and environmental factors like cold can also influence this.

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The Modifiable Factors

Lifestyle factors such as muscle mass, daily activity, and nutrition can influence your metabolism in meaningful ways. Muscle is the most powerful adjustable lever — it contributes about 20% of BMR, and unlike your organs, you can build more of it. At rest, muscle burns ~6–10 calories per pound per day. While that may seem modest compared to organs, muscle’s real impact comes from movement: every extra pound of muscle not only burns calories at rest but also makes walking, climbing stairs, or carrying groceries more metabolically costly.

Therefore, incorporating exercise that challenges the skeletal muscles would contribute to a higher overall basal metabolic rate, and therefore, more calories while engaging in daily activities as well as at rest. Two days of strength training, at the very least, can make a difference. Incorporating cardiovascular exercise in conjunction with a strength training regimen will only support further calories burned throughout the day.

Meanwhile, choosing a diet richer in protein and fiber leverages TEF, boosting calorie burn through digestion while helping preserve lean mass. Coupled with an active lifestyle — both intentional exercise and daily movement — these strategies give you real influence over your metabolism.

So if you want to boost your metabolism, focus on the levers you can actually pull:

1. Build and maintain muscle.
2. Eat protein- and fiber-rich foods.
3. Stay active throughout the day.

These facts are not as sexy or as easy as taking an expensive “metabolism-boosting supplement,” but it really is the best information we have based on solid evidence. At Hygeia, we design programs around these modifiable factors — helping you build lean mass, fuel smartly, and stay active in ways that elevate both your metabolism and long-term health.