Leptin is a hormone that comes from fat cells. It helps control food intake by sending signals about hunger to the hypothalamus in the brain. This process regulates appetite.

Leptin regulates energy levels by maintaining a balance between hunger and appetite. The hormone triggers the body to respond by eating more when energy levels are low and eating less when energy levels are stable or high.

People who have high levels of body fat have high circulating levels of leptin.

Research shows that having elevated leptin levels can lead to leptin resistance, making weight loss difficult.

This article looks at what the leptin hormone is, what the leptin diet involves, and the advantages and disadvantages of following the leptin diet.

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Scientists discovered leptin, a protein that functions as a hormone, in 1994.

Leptin is one of the main hormones responsible for maintaining body weight. Leptin helps people balance how much food they consume by regulating hunger levels. The hormone also controls how much energy a person uses throughout each day.

Leptin comes from fat cells within the body. It enters the blood supply and travels up to the brain. The hormone must cross the blood-brain barrier, a membrane that protects the brain from harmful toxins, to get to the hypothalamus. The hypothalamus is the area in the middle of the brain that controls hormone regulation, among other important functions.

At the hypothalamus, leptin can function by signaling that the body does not need any more food. This response causes the person to feel “full.” If leptin levels are low, or leptin does not reach the hypothalamus, a person will continue to feel hungry.

Leptin regulates body weight and is an important marker for energy storage. This means if the body has excess energy stored as fat, leptin signals the hypothalamus to reduce appetite and burn excess body fat for fuel. This response helps a person maintain a moderate body weight.

However, when a person has high amounts of body fat, they can develop a resistance to leptin, which leads to abnormally high leptin levels.

Having leptin levels that are too low is less common. Low leptin levels can occur in severe childhood obesity and delayed puberty.

When leptin levels are below average, the brain thinks no body fat is present. This reduced level can cause symptoms of uncontrollable hunger, resulting in excessive food intake. Leptin injections are a way of reducing this problem.

After scientists discovered the hormone in 1994, Byron J. Richards created a diet named after it: the leptin diet.

The goal of the leptin diet is to return leptin levels to normal and create balance within the body. The leptin diet has five main principles:

  1. Never eat after dinner: Not eating food at least three hours before bed enables leptin to function more efficiently at night. This includes burning fat and keeping hormones on track during sleep.
  2. Stick to three meals per day: A person should allow 5–6 hours between meals, without snacking in between. Snacking causes triglycerides (a type of blood fat) to build up, making it harder for leptin to reach the brain’s receptors.
  3. Never eat large meals: To help prevent the body from producing too much leptin and becoming leptin-resistant, people should eat slowly. This may also curb overeating.
  4. Eat a high-protein breakfast: People should include 20–30 grams of protein in each breakfast. Protein can prevent energy crashes, cravings, and a spike in blood sugar levels.
  5. Reduce carbohydrates from the diet: Most diets contain too many carbohydrates. When carbohydrates aren’t burned up, the body stores them as fat. Reducing carbohydrate intake is better than eliminating it altogether. A person should exercise portion control and eat meals slowly, as it takes 20 minutes for the hypothalamus to alert the body that it is full.

The leptin diet permits most types of food, but guidelines suggest avoiding chemical additives and processed sugars and sticking to fresh and organic produce.

The leptin diet encourages other lifestyle changes, such as getting plenty of sleep and participating in regular physical activity.

A 2021 study suggests that diets high in fat, carbohydrates, fructose, and sucrose and low in protein are drivers of leptin resistance. The researchers concluded that leptin resistance might be reversible by reducing calories.

However, this research has some limitations, such as small sample sizes, so further evidence is required to verify these claims.


The leptin diet includes limiting snacking and shortening your daily eating window. If a person reduces how much they snack, this could create a calorie deficit necessary for weight loss.

A leptin diet is a sensible approach to weight loss for some people, as the diet promotes eating healthily without harsh restrictions but encourages a routine.

However, at present, no studies are investigating the effects of the leptin diet on weight loss and leptin levels.


It is important to remember that all bodies are different, and a diet that meets the nutritional demands of one person will not always work for someone else.

For example, limiting the number of meals to three per day and cutting out snacking may be effective for a person with a low activity level. However, it is unlikely to meet the energy demands of a person who leads an active lifestyle, exercises intensely, or has a physically demanding job.

Many factors can impact energy needs, including age, pregnancy, breastfeeding, and certain medical conditions.

A person should consider consulting a healthcare professional like a registered dietitian if they are interested in improving health through dietary changes.

Increasing research suggests that obesity causes people to develop leptin resistance.

When someone carries an excessive amount of body fat, they will have too much leptin circulating in the blood. This excess results in that person becoming leptin-resistant. This resistance means their brain stops responding to the leptin signals traveling up to it. It also means their body continues to produce leptin, contributing to elevated leptin and leptin resistance.

Research suggests that weight loss and energy-restricted diets may help reverse leptin resistance.

Leptin is the hormone that controls appetite. Leptin informs the brain when a person has eaten enough, reducing appetite, and produces hunger signals when a person requires energy.

As with any weight loss plan, a person should approach the leptin diet with caution. The diet may be effective for some people, but it may not meet the nutritional demands of every person. Check with a doctor before starting any significant weight loss diet.