What’s the difference between weight loss vs fat loss?
Most people tend to use scales to measure their weight, but the truth is that scales don’t give you all the information about what you’re losing!
If you’re thinking about losing weight, what you probably actually want to lose is unneeded excess body fat. But, when you lose weight, what are you actually losing? Is it all fat, or are there other things being lost as well? To understand what’s being lost we need to look at some of the components of weight loss to help us:
Body weight – It’s not just the fat that you’re weighing when you stand on the scales. Your total body weight includes the weight of your muscles, fat, bone tissue, internal organs, and water.
Body composition – This is the ratio of how much fat you have to lean body weight (for example muscle, bone, internal organs etc). Body composition can vary from person to person (even if they are the same height and weight), and for an individual if they are gaining or losing weight.
Imagine two men (let’s call them David and Mark) who both weigh 200lbs.
- David has a body composition of 40lbs (or 20%) body fat and 160lbs (or 80%) lean body weight.
- Mark has a body composition of 80lbs (or 40%) body fat and 120lbs (or 60%) lean body weight.
This makes Mark overweight, but more importantly over fat (carrying too much fat) and puts him at increased risk to his health.
So, even though they are the same weight, David has a much better and healthier body composition ratio than Mark. But, if Mark lost 20lbs (10%) of fat his body composition would change. He would now have reduced his body fat to 60lbs (30%), meaning that his lean body weight of 120lbs has increased from 60% to 70%, giving him a better body composition ratio (and less risk to his health).
Weight Loss – When you see weight loss on a scale, it’s not just fat that you’ve lost. It’s also a loss of water, stored carbohydrates (called glycogen in the body) and some muscle. So, when you lose weight, the equation below shows what you tend to lose.
Weight loss = Some fat loss + some muscle loss (protein) + water loss
But what you lose can also change from week to week. For example, over a four week period the ratio of fat, water and protein being lost can change on a weekly basis. For many people on a calorie restricted diet this would typically look something like:
Fat, protein and water loss on a 4 week diet.
Week 1
Fat = 25%
Protein = 5%
Water = 70%
Weeks 2 – 3
Fat = 70%
Protein = 10%
Water = 20%
Week 4
Fat = 85%
Protein = 15%
So, while it’s great that you are losing fat, you can also be losing water and muscle mass (protein). Losing muscle mass can be bad because it is metabolically active and uses a lot of energy. Any muscle lost will reduce your metabolic rate, meaning that you need less energy. So when you start eating your normal diet again, those extra calories which are no longer needed (due to losing some muscle), will be stored as fat and you start gaining weight again.
Water is lost quickly because it’s linked with carbohydrates (glycogen) which is stored in your body. For every unit of glycogen, there are three units of water linked with them. So, when you cut back on the carbohydrates you eat, or you use up your stores in your body, you’ll have less glycogen, and also less water. This is why it’s easier to lose a lot of ‘weight’ at the beginning of diet. If you lose 1lb of glycogen, you’ll also lose 3lb of water (4lb in total). While this sounds great, as soon as you start eating more carbohydrates again, you’ll put the water back on and regain the weight quickly.
Fat Loss – This is a when you lose fat to lower the percentage of it you’re carrying on your body. Most people want to do this when they want to lose ‘weight’, usually to become healthier and feel and look better. Aiming to lose fat without losing muscle mass is a better way of losing weight as it keeps your metabolism higher. Effective weight loss should look something like this:
Weight loss = Mostly or nearly all fat loss + little or no muscle loss + little water loss
One of the best ways to achieve this can be eating healthy proportional meals, being in a negative energy balance and increasing the amount of exercise (strength training and cardio) you do. Strength training helps you prevent muscle breakdown while you are losing fat.
So remember …………..
