Some factors that promote weight loss are within your control, but most are not. Here’s what you can do to support your metabolism.
If you’ve ever attended a group fitness class where everyone’s heart rate and estimated calorie burn are displayed on a screen, you know that these stats vary widely from person to person. You’ve probably also noticed that in general, men tend to burn more calories than women. But have you ever wondered why different people burn calories at such different rates, even during the same workout?
The truth is that metabolism, an umbrella term for all the processes in your body that break down nutrients to produce energy, fuel growth, and more, is far from simple. There is a constant ebb and flow of reactions that build or repair our bodies (anabolism) and reactions that break down food and energy stores into fuel (catabolism). It is an extremely complex and very difficult subject to study. Different factors affect how fast or slow you burn calories at any given time.
Here are the six factors that have the biggest impact on the number of calories you burn while exercising.
1. Body weight
In general, the more you weigh, the more calories you burn per session. Calories are just a measure of energy, so the more you weigh, the more energy it takes to move your body In other words, of two people of different weights, the one who weighs more will burn more calories, because it has a greater energy expenditure when it moves.
Tall people also tend to have larger internal organs (such as the heart, liver, kidneys, and lungs), which is a major factor in the amount of calories burned during exercise and at rest. . Because these organs and their processes require energy. One study found that up to 43% of the variation in total calorie expenditure between people could be explained by differences in the size of their internal organs.
This is one of the many reasons weight loss is so complicated. Your body burns fewer calories as your weight decreases, which can lead to a weight loss plateau or even weight regain. That said, that’s not the only reason. A previous study explains that weight loss can also trigger other physiological adaptations, including the body’s tendency to burn stored fat for energy, a process called fat oxidation; an increase in hunger, due to higher levels of the hormone ghrelin and a decrease in satiety, due to lower levels of the hormone leptin.
If you’re looking to lose weight and you’ve hit a plateau, consider working with a dietitian who specializes in weight loss and can help you reach your goal in a healthy and sustainable way. Also, keep in mind that exercise is good for overall health, whether you lose weight or not. A study published in October 2021 in iScience suggests that while increased physical exercise generally does not lead to long-term weight loss, improved cardiorespiratory fitness is associated with better health outcomes. and a lower risk of premature death, regardless of weight.
2. Muscle mass
This is where things get a little complicated. A person with more muscle mass will burn more calories than someone with the same weight but less muscle. Muscle tissue burns more calories than fat tissue. Yet claims about how many calories a pound of muscle burns are often greatly exaggerated. In fact, a pound of muscle is proven to burn about five calories a day, while a pound of fat burns about two.
During exercise, more muscle mass will increase your total calorie expenditure because your body must produce more energy to support the increased rate at which your muscles contract. To sum up, if you want to increase your calorie consumption, consider stepping up your strength training. Lifting weights is proven to burn more fat (than cardio exercise) and the long-term results are more promising.
3. Sex at birth: male/female difference
In general, men burn more calories at rest and during exercise than women. But the reason isn’t magic, it’s because men tend to be taller than women, and they have more muscle mass than women of the same age and weight. Men typically burn 5-10% more calories than women at rest, and this percentage typically increases with exercise.
And while women can certainly add muscle mass through strength training, physiological differences mean that, in general, women cannot be as lean as men. Women are genetically predisposed to accumulate more fat to support hormone production and childbearing. This is because body fat is also essential for functions such as storing energy, protecting internal organs, and supporting key functions like growth, immunity, hormone production, reproduction, and health. metabolism.
Men need at least 2-5% body fat to be healthy, while women need a minimum of 10-13%. But these minimum numbers may not be sufficient. Although there is no official recommendation for the optimal percentage of body fat, the most cited study on the subject indicates that the healthy range for adults under 40 is 8-20% for men. and 21 to 33% for women. That said, the relationship between health and body fat is complex and not fully understood.
Instead of worrying about how your birth gender affects your calorie expenditure, focus on the things you can control. The key is for both men and women to focus on building muscle and improving cardiovascular health through a balanced program of cardiovascular and strength training.
As we age, we tend to lose muscle mass. After age 30, you begin to lose up to 3-5% of your muscle mass per decade. The reasons for this aren’t fully understood, but a July 2017 review in Aging Research Reviews says it’s likely because your body is becoming more resistant to hormones that promote protein synthesis, which is essential for maintaining muscle. This loss of muscle mass lowers your metabolic rate, the rate at which you burn calories, at rest and during exercise.
A study of human metabolism, published in the August 2021 issue of Science, made headlines for its findings that metabolic rate does not decline throughout adulthood, but rather plateaus between 20s and 60s, then would begin to decline. In this study, the authors measured the energy expenditure of 6,421 men and women aged 8 days to 95 years using the doubly labeled water technique, the gold standard for this type of measurement.
Although you can’t prevent your body from aging, you can preserve and even increase your muscle mass through regular strength training. Strength training can help increase your resting metabolic rate, which helps you burn more calories at rest over time.
5. Fitness Level
The more you do a certain type of workout, the easier it seems. It’s not in your head, your body actually adapts to do things easier over time. Overall this is a good thing. This means that you can run faster or longer with training, and your muscles will be able to lift heavier weights with proper training.
But it also affects your calorie expenditure. As your body adapts to the workout, you’ll burn fewer calories with the same workouts. From your lungs to your muscles, to your heart and brain, your body becomes more efficient as you get fitter. This is why a beginner can burn many more calories than someone who has been doing the same workout for years. That’s why changing your workout routine can increase your fitness level and potentially improve your calorie burn.
6. Workout Intensity
It’s also possible that two people doing the same workout will burn a different number of calories because they’re not doing the same workout. A person who trains at a high intensity, which means you breathe heavily and can’t hold a conversation, can burn twice as many calories in the same amount of time as a person who trains at low intensity. And just because you run the same distance as someone else, or perform the same moves, doesn’t mean you’re both training at the same intensity.
For example, walking and running have the same benefits in terms of reducing blood pressure and the risk of chronic diseases such as heart disease and type 2 diabetes. A previous study showed that adults who walk one kilometer burns about 89 calories, while adults running that same kilometer burn about 113 calories.
A goal of 150 minutes of low-intensity walking per week is enough to achieve many health benefits, including reduced anxiety, better sleep, lower blood pressure, better cardiovascular fitness, and reduced heart rate. risk or a slowing of the progression of certain chronic diseases.
Incorporating higher intensity exercise into your routine will increase your calorie burn and further magnify these benefits. To increase the intensity of your workouts, try increasing your speed, range of motion, or the amount of weight you use for resistance exercises.
Ultimately, you should try not to worry too much about things that are beyond your control. Exercise has countless benefits beyond just burning calories, and the most important thing is finding types of movement that are enjoyable and long-lasting. The type of exercise that is best for a person ultimately depends on their goals, physical fitness, and ability.