In order to stimulate fat loss, you need to understand how to balance your energy budget.

Our bodies store and burn fat based on the amount of calories we eat, store, and spend through activity and exercise.

What is a calorie?

Calories are one of the most useful ways to measure the food we eat and how it affects our bodies.

We use the term “calorie” to talk about the energy that our bodies get from food. “Calorie” in its everyday use actually a nickname for what scientists call a “kilocalorie” or “large calorie.” It is the amount of energy that it would take to raise the temperature of 1 kilogram water by 1 degree Celsius.

Everything your body does--including digestion, physical activity, and basic body functions--requires energy. We get that energy from the food that we eat. 

Almost everything you consume has calories. An apple has about 52 calories, a glass of 2% milk has 137 calories, and the average slice of cheese pizza has about 277 calories.

In general, if we eat more calories than our bodies can use, the extra energy will be stored as fat in our bodies. On the other hand, when we eat fewer calories than our bodies can use, we will use the energy stored in our body fat.

The average woman needs to consume about 2000 calories per day, and the average man needs about 2500 calories per day. However the exact number of calories each person needs is variable, depending on their age, height, body weight, and activity levels.

Although you can’t control your height or age, you can manage your body’s “energy budget” by changing the amount of calories you eat and the amount of physical activity you do every day.

If you want to lose fat, you have to put your body into a calorie deficit. In order to burn 1 lb. of fat, your body needs to burn 3500 calories more than what you eat. You can achieve that by eating fewer calories and burning more calories through increased physical activity. 

On a day to day basis, if you were to eat 250 calories more than your body can use, you would gain 1 lb of body fat in 10 days. On the other hand, if you were to eat 250 calories less than your body uses every day, you would lose 1 lb of body fat in 10 days. 

Body Fat or Water Weight?

Let’s take a look at a common claim that I hear from people doing “quick fix” diets, detoxes, and cleanses: “I lost 10 lb. in 2 weeks!”

While it is certainly possible to lose 10 lb. of body fat in 2 weeks, it is EXTREMELY difficult and NOT AL ALL RECOMMENDED.

Why? Well, let’s do the math…

In order to lose 10 lb body fat in 2 weeks, a person would have to be in a 2500 calorie deficit every day for 14 days straight to achieve a 35,000 calorie total deficit (the amount required to burn 10 lb of body fat). For both the average man and woman, that would mean going 2 weeks without eating anything! NOTHING.

As you learned above, nearly everything you eat and drink has calories. So unless the “cleanse” had you just drinking water and swallowing air bubbles for the entire 2 weeks, the likelihood is that you were eating something and at least getting 1,000 calories a day.

Maybe a few of the pounds you lost in those 2 weeks really did come from fat. However the majority of that body weight lost likely came from water.

Water makes up about 60% of your body weight. However the precise amount of water that your body stores has largely to do with what you eat and drink. Diets high in sodium and carbohydrates make your body retain and store water in your tissues.

When you eat carbohydrates, your body stores their energy in the short term as glycogen (housed in the liver and skeletal muscles). This is one of the first places your body will turn for energy when you begin to cut calories for weight loss. Glycogen is stored with lots of water, and when your body taps into this energy source, it also releases a lot of water. Your body turns to fat stores once these and a few other energy sources in your body (such as coming from protein and dietary fat) are depleted.

As you can see, getting your body to burn fat isn’t simple or fast.

The most aggressive fat loss program shouldn’t have you lose more than 2 lb of body fat per week. In order to achieve this, you would need to be in about a 7,000 calorie deficit every week--a daily deficit of 1,000 calories per day. 

For the average woman, this would mean eating 1,000 calories every day instead of 2,000. The average man would need to eat 1,500 instead of 2,500. 

There are some trainers out there who will bring their clients through this type of extreme fat loss program. 

I, however, do not recommend it. In my experience this Extreme Fat Loss method is a recipe for disaster. 

That’s because it is extremely difficult for a person to function in a 1000 calorie deficit. Hanger, light-headedness, and a perpetually growling stomach make it difficult to keep up with your day to day activities--much less exercise! More often than not, this method tends to lead to burnout and dropout. I’m more of a fan of methods that keep a person on track and healthy for the long haul.

I typically don’t aim to have my clients drop more than 1lb of body fat per week. 

To lose 1 lb of fat per week, you’d need to eat 3500 calories less than your body needs over the course of a week. On a day to day basis, this means eating 500 fewer calories than your body needs. Now this is still challenging--but much more doable than than the Extreme Fat Loss option described above.

Weight loss is a long-term balancing act that takes experimentation and lots of practice. It takes planning and consistency.

Yo-Yo Dieting and Your Metabolism

Going on and off of short term diets, detoxes, and cleanses can wreak havoc on your metabolism—making it difficult for you to lose weight even while consuming a low number of calories each day. If this is the case, you’ll need to do some careful planning to boost your metabolism and work your daily intake up towards a healthy maintenance level.

About the Author

Jayd Harrison is a personal trainer and content creator. She helps people to build muscle, burn fat, and clean up their diets with her online coaching programs and social media content. Check out some of Jayd’s coaching videos on Youtube, or join Jayd live on Twitch and follow on social media.