Staying alive burns calories. Even when you think you’re not doing all that much, you’re a breathing, blinking, blood-pumping, cell-growing, muscle-contracting machine. All of these functions that your body needs to sustain itself require energy in the form of calories – and the amount of calories needed for this is known as your basal metabolic rate, or BMR.
Put simply, if you were to (hypothetically) rest in bed for the entire day, your BMR would be the amount of calories burned to perform your body’s basic (basal) functions. The higher your BMR, the more calories you burn – simply by being alive.
There are a few strategies you can use to work out your BMR. For the most accurate results, you’d need to get it measured in a laboratory under restrictive conditions. Experts measure carbon dioxide and oxygen after you’ve fasted for 12 hours and had an eight-hour sleep. But there are other methods. By using a scientific equation, you can achieve a rough estimation of your BMR that’s still just as useful. The best is the Mifflin-St.Jeor method. Find the online BMR calculator here, which uses this equation:
For men: 10 x weight (kg) + 6.25 x height (cm) – 5 x age (years) + 5
For women: 10 x weight (kg) + 6.25 x height (cm) – 5 x age (years) – 161
The fact BMR is basically your metabolism means it plays a very important role when it comes to weight loss and weight gain. It’s your most basic calorie burn. Those with higher BMRs are the kind of people who can eat an insane amount of food and never gain weight. Obviously they’re at a genetic advantage, but there are plenty of ways you can work towards a higher metabolism and BMR.
Everyone’s BMR is different. Your age, gender, size, height, weight, mass and even the size of your internal organs (larger organs need more fuel) play a part in determining your number. There’s not much you can do to control your genetics, but you can influence your body composition with a few simple changes:
The best way to increase your BMR is to build muscle. Lean muscle mass torches more calories than fat and pumps up your metabolism. Functional training will help you build muscle more than regular workouts; the latter can be limited in terms of movements.
Another way to increase your basal metabolic rate is to eat the right amount of calories. That means no semi-starved states and the low BMR that comes with it. Men need to be eating around 2,500 calories and women need to eat 2,000 calories daily, according to the NHS. Munch on BMR-boosting foods such as hot peppers, green tea, broccoli, spices, citrus fruits and cacao.
Stress is another huge contributor to a low metabolism. A heightened rush of cortisol (the stress hormone) will send your body into “fight or flight” mode. As a result, less blood will be sent to the digestive system in order to deal with whatever threat the body is responding to.