When You Lose Weight, Where Does It Go?

In our society, we sometimes receive the message that body fat is something to get rid of, but the purpose of body fat goes far beyond physical appearance. The scientific term for body fat is "adipose tissue," which is an organ in the endocrine system responsible for the metabolism of energy, as described by the Cleveland Clinic

Body fat is important because it protects soft organs. It also manages glucose and cholesterol levels and releases hormones that communicate with other organs and the central nervous system. The body can have trouble regulating itself when it has too little or too much fat. For example, too little body fat can lead to malnutrition and too much body fat can increase the risk of heart disease and type 2 diabetes, according to "Introduction to Nutrition" (via LibreTexts Medicine). 

Subcutaneous adipose tissue is the type of body fat just beneath the skin that can be felt and pinched, as reported by Insider. Another type of body fat associated with diabetes, heart disease, and other conditions is called "visceral fat," which is located around the stomach, liver, and intestines. An unhealthy diet and lack of physical activity can contribute to excess visceral fat.

Many of us have tried to regulate our weight in the past, but have you ever wondered what actually happens to body fat when it's burned? It turns out that there's a physiological process that allows our bodies to expel body fat through our breath and other bodily fluids, as explained by MIT Technology Review

Where fat goes once its burned

We've all heard that exercise is beneficial for losing weight, but how is body fat shed during the process? A 2019 article published in the Bulletin of the National Research Centre explained that fat cells in the body use triaglycerol to release free fatty acids (FFAs) into the bloodstream that provide muscles with energy. FFAs are released in the mitochondria of fat cells when the body loses weight, decreasing the size of the cells and making the body appear thinner. On the other hand, fat cells will increase in size when they are filled, resulting in an increase in body weight. 

When fat is finally shed from the body, does it simply disappear into thin air? Some scientists believe that body fat can be released through water and carbon dioxide, as described by BBC News. A 2014 study published in BMJ-British Medical Journal discovered that fat could be exhaled from the lungs as carbon dioxide after being fully oxidized. "Our calculations show that the lungs are the primary excretory organ for fat," explained the researchers. Body fat can also be expelled by the skin and kidneys in the form of bodily fluids like sweat, urine, and tears. 

The body's respiratory rate increases during a workout, which allows more carbon dioxide to leave the body through the lungs, according to the Cleveland Clinic. It takes approximately 30 to 60 minutes of aerobic exercise for the body to transition from burning stored glycogen to burning fat. 

Losing weight in a healthy way

After finding out how body fat disintegrates when losing weight, you may be wondering how to lose weight safely and effectively. Maintaining a healthy weight can help protect against diseases associated with excess body fat, according to BetterHealth. However, reaching a healthy weight can be easier said than done. Common myths about weight loss can make it difficult to know where to start and may contribute to unhealthy eating patterns. 

Despite popular belief, diets aren't the most effective way of maintaining a healthy weight, and can even be harmful to your health in some cases. According to the Centers for Disease Control and Prevention (CDC), it's far better to work on two or three specific, realistic weight loss goals. Creating goals that are impossible to achieve can set you up for failure and make you feel bad about yourself. It's important to practice self-forgiveness and be gentle with yourself if you fall short of your weight loss goals, as some obstacles are normal and can even be expected. 

Recording details of your daily food intake and eating habits can provide insight into the changes you want to make, as explained by Harvard Health Publishing. Awareness of your eating habits can help you identify when your stomach is full or when you're experiencing emotional hunger, which can help with overeating. While working to maintain a healthy weight, it's also helpful to engage in physical activities you enjoy and seek out social support from others.