When it comes to weight loss, we hear a lot about metabolism, with many blaming ‘slow metabolism’ for being overweight. Here, we take a look at what factors affect metabolic rate, and how you can give yours a boost.
Truths and myths about metabolism…
Simply stated, the term ‘metabolism’refers to the chemical process by which the body converts calories from food into energy.
I can see how the term ‘metabolic rate’could confuse people. The word ‘rate’ suggests speed, so, it is understandable why many assume metabolic rate refers to how fast or slow your body performs.
In reality, your metabolic rate (or,more accurately, your resting metabolic rate) refers to the number of calories you burn during a 24-hour period just to keep your body’s most basic processes going – e.g. pumping blood and breathing.
Of course, this isn’t all the calories you burn in a day, but your resting metabolic rate accounts for a sizeable chunk. About 75% of the calories you use everyday are simply to keep your body ticking. Most of the remaining calories are used during daily activities and exercise.
What factors influence metabolic rate?
While some people’s bodies use more calories to perform these basic metabolic processes than others (often referred to as ‘fast metabolism’), metabolic rate isn’t about how quickly you burn calories; it’s about the number of calories you burn each day. So while you can’t technically make your body burn calories any faster, you can help it become more effective.
Here is my quick guide to what factors affect metabolic rate:
- Body size
Larger people have higher metabolic rates than smaller people; simply because they have more cells, each of which is performing metabolic work.
- Body composition
Lean body mass plays a big part in metabolism effectiveness. Every pound of lean muscle burns about 14 calories per day, while a pound of fat only burns about 2 calories per day. Muscle cells have a lot more machinery that convert calories into energy than fat cells do, so it makes sense that as muscle mass increases, so does metabolic rate.
The natural hormonal changes that come with age cause most people to lose muscle mass. The body becomes less effective at repairing muscle damage from general wear and tear, causing a decrease in muscle cells. As a result, the body is able to burn less calories.
Men often have higher metabolic rates than women as they tend to be larger overall, with more muscle mass and therefore more calorie-burning cells.
- Cutting calorie intake too much
Cutting your calorie intake too much can cause metabolic rate to decline, as the body is trying to do the same metabolic work, but with fewer calories. However, these decreases are relatively small, especially if changes in calorie intake are only modest, rather than dramatic.
How to boost metabolic rate…
- Eat more protein. The body uses protein to build and repair muscle tissue. Without this, the body cannot sustain muscle cells and help them to increase metabolic rate.
- Build muscle mass. This increases lean body mass, which helps to raise your resting metabolic rate.
- Increase daily activity. Exercise forces the muscles to work, which helps to preserve lean body mass, and hence increase metabolic rate. Increased activity can also help to offset any dips in metabolism caused by reduced calorie intake.
Written by Susan Bowerman, MS, RD, CSSD. Susan is a paid consultant for Herbalife.