Weight loss is a goal many people have at some point in their lives and there is an abundance of information and diets out there telling you how to achieve this goal. Despite all this information, and what the diet industry would like you to believe, is that weight loss is difficult. Yet at its core, weight loss is simple maths – calories in verses calories out. Today we will look at what calories are, how they work and how you can manipulate them to help you lose weight.
Let’s start by looking at what calories are.
Calories are a measurement of energy. A single calorie, known as a gram calorie, refers to the amount of energy needed to raise one gram of water by one degree Celsius.
The calories you are most familiar with are food calories or kilocalories. One food calorie equals 1000 gram calories and is the standard means of measuring the amount of energy in the food you eat. With the exception of water, everything you eat and drink contains calories and these calories provide energy to your body.
The amount of calories in your food is mainly determined by fat, protein and carbohydrates, known as macronutrients. All foods contain one or more of these macronutrients and each one contain a different amount of calories or energy. Carbohydrates and protein each have four calories per gram while fat has nine calories per gram and alcohol has seven calories per gram. In simple terms this means 100 grams of pure protein has 400 calories while 100 grams of pure fat has 900 calories.
When you see the calorie content of your favorite food, what you are seeing is the amount of energy that food will provide based on its unique mixture of fat, protein and carbohydrate.
So how do calories work, now that you know what they are?
Every person needs a certain amount of energy every day for basic human function and to keep their body alive. Calorie intake is an easy way to measure and determine just how much energy you need and to make sure you are getting the right amount.
How much energy or how many calories you need each day depends on your age, gender, height, weight and activity levels. You may have heard others talking about metabolic rate and metabolism. Your metabolic rate and metabolism is the amount of energy your body uses each day to support your heart, lungs, and brain function, to digest food, to exercise and to simply live and complete your daily tasks.
Your resting or basal metabolic rate is the minimum amount of energy you need each day for these functions if you were at complete rest. Because very few people are at complete rest all day, the amount of calories you need takes into account any activity you do, no matter how heavy or light. Extra movement means extra energy to fuel the movement.
So what exactly does this mean?
It simply means that a male of average height and weight who doesn’t do any activity during the day would need less calories or energy than a male of the same height, weight and age who is active all day.
Seems pretty simple right? And it is. Let’s look at it in terms of weight.
Every time you eat or drink, you are taking in energy to fuel your body and every time you exercise or perform an activity, you are using energy. When you take in enough energy or calories each day to meet your body’s needs, your body uses that energy for its daily functions and your weight remains the same.
Remember when I said weight loss was simple maths?
When you take in more calories than you need, your body stores this extra energy and you put on weight. When you take in fewer calories than you need, your body uses its stored energy to make up the difference and you lose weight.
Let’s say you need 2500 calories a day based on your height, weight, age, gender and activity level. If you consume 2500 calories throughout the day, your body receives all the energy it needs and doesn’t need to store or use any extra.
If you were to consume 3000 calories a day instead of 2500 calories, your body will first use those 2500 calories and then store the remaining 500 calories for later use. Many people believe that these extra calories are stored the same way they are received: that fat is stored as fat, protein is stored as muscle and carbohydrate is stored as sugar. This isn’t the case. Your body doesn’t care where the calories come from, just that it has them, so extra calories are stored as energy and lead to weight gain in the form of extra body fat, regardless of the type of calories you ate. Extra energy is extra energy and if your body doesn’t need to use it, it simply stores it.
On the other hand, if you were to eat only 2000 calories a day instead of 2500 calories, your body will use those 2000 calories first and then find the extra 500 calories it needs by releasing some of your stored energy or extra body fat.
Generally, when you are trying to lose weight, the goal is to lose stored body fat. In some cases, your body may burn stored sugar or glycogen first before burning fat and in some extreme cases, it will break down muscle tissue for extra energy. The good news is, you are able to manipulate calories and your body’s stored energy to lose weight and it is easier than you think.
The first thing to remember is that HOW you get your calories is less important that how many you consume. Although the calorie values of macronutrients differ, a calorie is a calorie no matter where it comes from. If you need 100 calories, your body doesn’t care if it’s 100 calories of protein or fat or sugar, so long as it’s 100 calories.
The second point to remember is to take in fewer calories than you need each day. Even if you only eat 100-200 calories less, you will lose weight over time because your body will be forced to find those extra calories from stored energy.
The third point to know when manipulating calories for weight loss is exercise. Most people focus on low intensity or steady state cardio when trying to lose weight – for example, walking at the same speed or intensity for a long period such as 60% effort for 60 minutes. Now, there is nothing necessarily wrong with exercising this way, you will burn calories but you will only burn them while you exercise.
If you are trying to manipulate calories and burn more stored energy, high intensity exercise is a much better idea. High intensity exercise means exercising at a high intensity level such as 80-90% effort for shorter period of time such as 20-30 minutes.
On the surface, you burn fewer calories because you are exercising for less but high intensity exercise keeps your metabolism raised long after you finish exercising. This means you can continue burning calories for up to 24 hours after your exercise session.
Let’s say a 60 minute walk burns 400 calories. Your heart rate and metabolism are only raised while you are walking and return to normal when you are finished. If you complete 20 minutes of high intensity exercise you might burn 200 calories. After you are finished you heart rate will return to normal but your metabolism stays high. If it stays high for an hour after your session, that’s an extra 600 calories you have continued to burn, bringing your total to 800 calories.
Now if your body needs 2500 calories, and you have only eaten 2000 calories, and then burn 800 calories through exercise, that’s 1300 calories your body needs to take from stored energy. Do this four or five times a week and that’s a lot of stored energy your body is using!
As you can see, the basics of weight loss are simple. Create a calorie deficit either by eating less or exercising and your body is forced to burn stored energy to get the extra calories it needs to meet your daily needs. Best of all, you can choose how you create this deficit and manipulate your calorie needs to lose weight.