Essential guide to metabolism

Contrary to popular belief, the majority of your daily calorie burn doesn't come from puddles of sweat after a tough workout. Calorie burn is driven by your metabolism. Metabolism is the entire process of converting calories into energy to power your bodily processes. It isn't just about calorie burning. It's also about calorie storing. Your metabolism determines the number of calories you need daily to maintain your weight.

THREE SCIENCE-BACKED WAYS TO BOOST YOUR METABOLISM There's a lot to learn about metabolism, but most of us just want to know how to increase it. If you notice a weight-loss plateau, you could be overestimating your calorie burn.

Here are three ways to boost metabolism.

INCLUDE STRENGTH TRAINING IN YOUR EXERCISE ROUTINE

Adding muscle mass increases your BMR, the biggest contributor to your overall metabolism. This will allow you to burn more calories even when you aren't exercising.

UP YOUR WORKOUT INTENSITY During an aerobic exercise (running, swimming, biking, HIIT), add intervals so you can benefit from after burn, a phenomenon where you burn extra calories after exercise.

EAT ENOUGH PROTEIN

High-quality protein sources will give you all the amino acids needed post exercise to help muscles repair and grow.

TYPES OF METABOLISM While there's only one way calories can enter your body (nom nom!), there are many ways for calories to leave it. Here are the three major factors that affect your metabolism and overall calorie burn.

BASAL METABOLIC RATE (BMR): CALORIES TO SURVIVE

BMR accounts for 60-70% of the daily calories you burn. Basal metabolic rate is the number of calories your body needs at rest to support the vital functions that keep you alive (breathing, digesting, filtering waste). Your BMR doesn't include the calories you burn for normal daily activities or exercise.

Here are the key factors that play into BMR:

Body Size: A bigger individual requires more calories to sustain their body at rest and with any activity they do.

Body Composition: Muscle is more metabolically active than fat, meaning more calories must be burned to maintain a pound of muscle compared to a pound of fat. Two healthy individuals of the same age, height and weight can have very different BMR if they have significantly different percentages of lean versus fat mass. Since most women have more fat mass compared to men, they have correspondingly lower BMR compared to men of the same height and weight.

Age: Your BMR is higher when you are younger, especially since calories are needed to supply your growing body. The trend is that as you age, you slowly gain weight in the form of fat mass and lose weight in the form of muscle mass.

Genetics: Some people are born with higher (or lower) BMR than others, and this is completely normal. Your genes are not something you can fix, but if you suspect you have a genetic condition that slows your metabolism (such as familial hypothyroidism), you should consult a doctor.

Hormones: Hormones act like chemical dials allowing your body to turn your metabolism up or down depending on its needs. The two main hormones (thyroxine and triiodothyronine) directly responsible for turning up BMR come from your thyroid gland. Other hormones indirectly cause your thyroid gland to release more or less of these hormones, leading to a change in BMR.

Health: Generally, your BMR is higher when you are fighting off an infection or healing from a major wound. This is because your body requires more calories to accomplish both of these tasks.

FOOD THERMOGENESIS: CALORIES TO DIGEST

Accounts for 10% of the daily calories you burn. It may not be an easy word to say, but the concept is somewhat simple. Food thermogenesis is the energy (calories) you need to digest and absorb food, protein requires the most work to digest followed by carbs and fat. About 10% of your daily calorie intake is used to digest and absorb a meal but here's the breakdown:

About 3% of the calories from the fat you eat are used to support its digestion. About 10% of the calories from the carbs you eat are used to support its digestion. About 30% of the calories from the protein you eat are used to support its digestion.

A high-protein, low-carbohydrate diet tries to leverage this phenomenon to burn calories, as it takes more energy to burn protein than carbs or fat. Since food thermogenesis only accounts for 10% of your daily calorie burn, eating more protein will only have a small effect on your metabolic rate. While protein is still helpful for weight loss, you need to consider the cons of eating too much, including the wear and tear on your kidneys.

PHYSICAL ACTIVITY: CALORIES TO MOVE Accounts for 20% of the daily calories you burn. For most people physical activity accounts for 20% of daily calories burned, but this percentage can be higher on tough workout days. Keep in mind that it's not just about the calories burned while working out; it's also about the calories burned while working on the job (typing, carrying heavy loads, standing, fidgeting) and having fun (shopping, playing, singing).