Weight loss is an issue that attracts the interest of many people around the world. It’s important to understand how your body burns calories and the science behind weight-loss strategies. Understanding the complex processes can help you make better decisions and create more effective strategies to achieve your weight loss goals.

What is Weight Loss?

When you burn more calories than you eat, you lose weight. This concept is based on the principle of energy equilibrium, which is often called the “caloric surplus.” You need to create a deficit of calories in order to lose weight. This means that the energy you use (through metabolism and physical activity), must be greater than the energy your body receives from food and drinks.

Calories are energy units derived from macronutrients: carbohydrates, protein, and fats. Each macronutrient contributes in a different way to the body’s need for energy:

Carbohydrates are a good source of quick energy.

Proteins are important for muscle growth and repair.

Fats: They are a source of long-term energy and they support various bodily functions.

If you are in a caloric deficiency, your body will tap into its reserves of energy, which are primarily stored as fat, to compensate. This leads to the burning and release of fat stored in your body, resulting in weight reduction.

Science behind fat storage and release

Understanding how your body releases and stores fat is essential for understanding the process. Adipocytes (also known as fat cells) play a key role in this process.

Fat Storage

Triglycerides are stored in fat cells. The excess calories you consume are stored in fat cells when you consume more than your body requires for immediate energy expenditure. Over time, these triglycerides accumulate and can lead to weight gain.

Hormones and Fat Releasing

Insulin and glucagon are the two main hormones that regulate fat storage.

Insulin: After eating carbohydrates, insulin is released. Insulin is responsible for transporting glucose into the cells to be used immediately as energy and promoting fat storage.

Glucagon – On the other side, glucagon can be released when your body requires more energy than is in your bloodstream. This may happen during times of fasting or physical activity. Glucagon tells fat cells to breakdown stored triglycerides, releasing free fatty acids and glycerol. These can then be used by different tissues as a source for energy.

Insulin and glucagon interact to determine whether your body is fat-storing, or fat-burning. Other hormones such as growth hormone and adrenaline also play a part in regulating the release of fat.

Lipolysis is the breakdown of fat

Lipolysis is the breakdown of triglycerides in fat cells. This process is a series enzymatic reaction that leads to the release of fatty acids free and glycerol in the bloodstream. Once these molecules are in the bloodstream they can be transported into cells all over the body to use for energy.

Fat loss is a process that involves the entire body. You can’t spot-reduce the fat in specific parts of your body. Your body releases energy from fat reserves based on hormonal and genetic factors.

Metabolism and Fat Burning

The term metabolism is used to describe all chemical reactions within the body that are necessary for life. It is divided into two categories:

Anabolism is the process of building molecules such as proteins and glucose.

Catabolism is the process of breaking down molecules such as carbohydrates and fats to release energy.

Catabolic processes are the primary cause of weight loss, as your body uses stored fat to produce energy. The rate at which you burn energy is called your metabolic rate. It plays an important role in determining how quickly and efficiently fats are burned.

Resting Metabolic rate (RMR).

The Resting Metabolic rate (RMR) is how much energy your body needs to perform basic functions at rest such as breathing or cell maintenance. If your RMR is higher, you will burn more calories when at rest. This can help with weight loss.

There are many factors that can influence your RMR. These include genetics, age and body composition. As muscle tissue needs more energy to maintain, it tends to be higher in RMR.

Thermic effect of food (TEF)

The Thermic Effect of Food is the amount of energy used during digestion and absorption of nutrients. TEF rates vary between macronutrients:

Proteins: Digestion of proteins is the most energy-consuming, with a TEF between 20-30%.

Carbohydrates – The TEF of carbohydrates is between 5-10%.

Fats: Fats are the least TEF-ed, usually around 0-3%.

You can potentially lose weight by increasing the energy expenditure of digestion.

Exercise and Physical Activity

Exercise and physical activity are important contributors to fat and energy loss. Your body uses calories as fuel to perform physical activities such as walking, jogging or swimming. The longer and more intense the exercise, the more calories are burned.

Aerobic exercises such as cycling or running are effective in burning fat because they increase your breathing and heart rate, which increases calorie expenditure. Strength training is also important, because it preserves and builds muscle mass. This, in turn boosts RMR.

Non-Exercise Activity Thermogenesis

Non-Exercise Activity Thermogenesis is the amount of energy used during non-exercise activity, such as standing, walking, or fidgeting. Even small changes to daily habits such as standing instead of sitting or taking the stairs rather than the elevator can increase NEAT.

How to Optimize Fat Burning

It’s important to understand the science behind fat burning, but you also need to know how to use this knowledge in your weight loss journey. Here are some tips on how to maximize fat burning.

Create a Caloric Deficit

You must create a caloric surplus by consuming more calories than what you burn. A caloric deficit between 500 and 1000 calories per day will result in weight loss that is safe, usually 1-2 pounds a week.

Prioritize a balanced diet

It’s important to consider the quality of your food as well as the caloric deficit when attempting to lose weight. Choose foods rich in vitamins and minerals. Include a wide range of macronutrients with an emphasis placed on lean protein.