Many people ask me why their metabolism seems to change with weight loss and the answer is not a simple one. What is often forgotten is that the body is a complex machine, with many hormones, chemical reactions and mechanisms keeping us operating. The body works daily to maintain the weight it wants us at, regardless if it is optimal from a health standpoint.

What is your metabolism?

Simply put, your metabolism is the way your body converts the food and liquids you consume into energy. Your metabolism is sophisticated network of organs, hormones and chemical reactions occurring on the cellular level to perform daily functions. The body needs energy all the time, even when at rest or sleeping. Calories burnt by your body in normal everyday activities like walking to work, climbing stairs, or even getting up and sitting down play into it. Studies have also shown that your metabolism manipulates itself to keep your weight at a place it favors-yes, even when you eat less and move more.

What affects your metabolism?

Everyone’s metabolism is unique and is affected by a combination of genetics, environment and personal anatomy. Some people naturally have faster metabolisms than others. We all know someone like this. They appear to be able to eat exactly what they want and never gain an ounce. Not all of us are so lucky.

While we can’t do anything about the genetics, we can improve our environment and body composition to help keep us healthy. We can do this by making healthier choices that include plenty of protein, healthy fats and fiber. In addition to proper sleep, exercise and stress management to improve your metabolic health.

Your metabolic health is important as it affects mood, immune health, risk of chronic disease and inflammation levels.

What does weight loss mean for your metabolism?

Our bodies fight daily to keep us in a balance it desires. This means that when we decide to lose weight, our metabolism kicks in to defend itself and hold on to the weight thus sabotaging our efforts.

Why is that? Our bodies still have our primal instincts to keep us alive during times of famine. When we cut calories we trigger this survival mode regardless if the weight loss was intentional. When we enter this survival mode, our body plays a few tricks on us to try and get us back to the original weight. The most important - slowing down our metabolism.

It does this because our bodies are designed to be efficient and store energy when possible. With weight loss and a smaller body, you simply need fewer calories to fuel it, in the same way that a large room requires more heating than a smaller one. The result? Your body, even with activity, tends to burn fewer calories.

You also start to feel hungrier and less satiety with weight loss.

Leptin is a hormone that helps increase metabolism and reduce appetite. Unfortunately, as weight is lost the levels of leptin drop, slowing your metabolism, and making you hungrier. This happens in part because many leptins are produced by fat cells, and as you lose weight, you lose the fat cells that produced the hormones.

Losing weight also lowers the amounts of incretins that are released by the gut, these are other hormones that help to regulate appetite. This is why people who have successfully shed excess pounds can often start to gain weight again. Your brain is constantly signaling you to eat more.

How To Help Your Metabolism

However, it is possible to reset your metabolism! Although your body is having a tug of war with itself, it is possible to keep the weight off. Using what we know about our metabolism, we can create a sustainable and scientific approach to long term weight loss. If you struggle with weight loss, it can result from a variety of underlying biological factors including hormonal, metabolic, and genetic factors. If you are looking to start your weight loss journey and reset your metabolic health I offer in-person services through my clinic, learn more here. 

Dr. Nancy Rahnama, MD, ABOM, ABIM, is a medical doctor board certified by both the American Board of Obesity Medicine and the American Board of Internal Medicine. Her specialty is Clinical Nutrition, that is, the use of nutrition by a medical doctor to diagnose and treat disease. Dr. Rahnama has helped thousands of people achieve their goals of weight loss, gut health, improved mood and sleep, and managing chronic disease.