Obesity and overweight have become serious worldwide problems, affecting children and adults. As it is estimated, over 43% of Americans have obesity, while 30.7% are overweight. People with obesity have high levels of leptin. According to some suggestions, leptin is one of the four hormones determining weight. However, no proper research supports such a simplified approach since many hormones and factors are involved in weight control. Let’s dive into the topic to check how obesity and leptin are connected.
How to calculate BMI?
Body mass index (BMI) may help to determine whether you have a healthy weight. For the calculation of BMI, it is necessary to divide weight (in kg) by the square of height (in m). For adults aged 20 and older, the WHO defines BMI based on the following standard weight status categories:
- Underweight: BMI below or equal to 18.5;
- Normal: BMI varies from 18.5-24.9;
- Overweight: BMI varies from 25.0-29.9
- Obese: BMI greater or equal to 30.
These weight standards are the same for men and women of all body types.
What is leptin?
Leptin, also known as a satiety hormone, is produced and secreted by the adipose tissue (the body’s fat cells) to maintain a healthy weight. It releases into the bloodstream and signals to the brain to inhibit food intake and burn calories normally. The signals help to regulate hunger by providing the sensation of satiety.
Earlier scientists made hypotheses that leptin has a weight loss effect, but further studies showed that leptin isn’t the weight loss pill.
At the same time, leptin doesn’t affect your appetite and food consumption level but rather helps to control the long-term balance between energy expenditure and food intake to maintain a normal weight so that your body won’t urge a hunger signal when it doesn’t need calories.
In fact, leptin levels increase exponentially, not linearly, with fat mass. That means that excess weight can lead to leptin levels increase.
Obesity and leptin: everything you need to know
Leptin has a more profound effect when you lose weight. When your adipose tissue decreases, leptin levels decrease too. It stimulates appetite and can lead to excessive food intake.
Exceeded food consumption increases body fat, leading to a leptin section increase, reducing hunger and appetite, and increasing energy expenditure by using brown fat. The more fat we have, the more leptin is produced. When the process functions normally, it keeps body weight in homeostasis.
As scientists are still studying leptin, there are a lot of controversial theories regarding this hormone. Some studies consider leptin as a multifunctional hormone produced by different organs and tissues: kidney, placenta, stomach, etc.
How are leptin levels controlled?
The main type of fat in the body is white adipose tissue, which is located beneath your skin, around organs, and in the middle cavity of bones. The amount of leptin in the blood is directly proportional to the amount of fatty tissue in the body. The less body fat the individual has, the less leptin is produced.
What is leptin resistance?
When your brain constantly signals hunger, even when you have a lot of fat cells and plenty of leptin, it’s called leptin resistance. Because of that, the brain stops receiving leptin’s signals and responding to them accordingly. As leptin constantly stimulates the brain, the individual won’t get the sensation of feeling full.
Leptin resistance not only contributes to eating more but also to entering starvation mode to save energy. Therefore, the brain decreases energy levels and makes the individual use fewer calories at rest. Thus, individuals always feel hungry, even when the body receives more than enough food to fuel.
What are leptin resistance symptoms?
The main symptoms of leptin resistance include:
- Junk food cravings. Individuals with leptin resistance are out of control of food cravings, especially for junk food. You will urge to snack soon after the meal. Try to make at least 4-5 hour break between the meals, and don’t let yourself snack. When you fail to do such breaks, you are dealing with leptin resistance.
- Weight gain. People who resist leptin constantly feel hungry, even when their body is full. Increased food intake leads to excess amounts of body fat.
- Fatigue. People with leptin resistance may be less physically active because the brain doesn’t respond to the signals telling it to burn calories respond to the signal telling it to burn calories.
- Pain disorders: The high leptin levels in people with leptin resistance may make a person more sensitive to pain or more prone to developing chronic pain disorders.
What about leptin supplements?
As leptin is a hormone rather than a vitamin or mineral, you cannot absorb it from a pill. In fact, they don’t contain leptin, but caffeine or just a mix of herbs, which may suppress the appetite. They might not be harmful, but there’s no evidence they’ll have any effect on your leptin levels.
In terms of weight loss, more leptin is not necessarily what matters. How well your brain interprets its signal is much more significant. Therefore, taking a supplement that increases blood leptin levels does not necessarily lead to weight loss.