Many people believe there is a set calorie intake to lose weight. Have you ever gone on a 1200 calorie a day diet to get into that special outfit? Or seen ads for “1500 calories a day for staying slim”?
We tend to think that the easiest way to lose weight is to just restrict our calories for a short time, and then hey presto our willpower and dedication pays off and we can strut into our high school reunion looking fabulous.
But it doesn’t quite work out. Our pesky bodies try to undermine our willpower with cravings and overwhelming hunger. Or we lose the weight only to put it back on again along with some more pounds. Sometimes we just get to a certain point and plateau – no matter how much we reduce our intake, our body adjusts.
This is the number of calories your body needs in a day just to maintain vital functions such as breathing, heart rate, and processing food. It’s the number of calories you need before doing any activity.
If you reduce your calorie intake to lose weight without meeting your bodies minimum needs, it goes into survival mode. This has been a useful thing in our evolutionary history. If your body doesn’t have enough to sustain itself, it becomes very efficient with its fuel. It is like when you might be low on funds before payday. You ration your resources – consider your priorities and make them last.
So if your body doesn’t get its minimum calorie requirements, it slows down. Many “experts” dismiss the whole concept of metabolism as people’s excuse for overindulgence. But lowered metabolism because you have reduced your calorie intake lower than your Basal Metabolic Rate is a big downward spiral.
BMR is different for everyone, and at different times of your life. Here are 6 things that influence your Basal Metabolic Rate
Factors included in BMR Calculations
Age does tend to lower metabolism goes. As we age, we usually lose muscle and lung capacity (two very important factors in metabolism. Maintaining muscle mass and aerobic fitness can limit this factor. Our tiny energy factories (mitochondria) also become less efficient from damage.
The more you weigh, the more calories you need to pump blood, breathe and remove toxins and waste. So your metabolism is actually a bit faster when you are carrying more weight. What this means is as you lose weight, you need fewer and fewer calories. Doesn’t sound fair really.
Calculations of BMR often include height. The taller you are, the higher your BMR. So does this mean “I’m not overweight, just vertically challenged?”
Males metabolic rate tends to be higher and not just because they usually have more muscle mass. Testosterone levels have a big influence on muscle mass and metabolism. Women can indirectly increase their metabolic rate by increasing their muscle mass and testosterone levels.
Factors influencing BMR but not included in Calculations
These aren’t included when working out calorie intake for weight loss purposes. Think of them as bonuses (or otherwise)
Activity also affects BMR. Not only does activity burn more calories, it increases metabolism. The more active you are, the more calories you need. A lounge lizard lifestyle lowers the speed of your metabolism – it gets lazy too.
Two people can weigh the same, but have very different amounts of muscle. Muscle is vastly more active than fat and raises metabolic rate. Most BMR calculations don’t include the amount of muscle a person has.
By calculating your Basal Metabolic Rate you can make sure you get your minimum calorie intake to lose weight. Don’t go lower than this unless you want your body to conserve fuel and also break down existing muscle to get it’s basic energy requirements.