- Leptin, or the satiety hormone, plays a role in determining the body’s energy-balance system and regulating weight.
- Increased leptin levels result in decreased caloric intake, and decreased leptin levels result in increased caloric intake and body fat accumulation.
- Leptin regulation can be disrupted by excessive intake of calorie-rich foods that are high in fat and sugar due to the over-stimulation of the brain’s reward system and increased dopamine release.
- We can control leptin by decreasing our intake of processed, energy-dense foods, decreasing portion sizes, exploring methods of fasting, and monitoring stress, sleep, and inflammation.
If a woman of average height who weighs 110 pounds loses 40 pounds, most people would say that she was too skinny and possibly malnourished. Yet if a woman who weighs 310 pounds loses 40 pounds, many people would congratulate her for shedding the excess weight. To society, there is a big difference in experience between these two women on a diet. Yet to the human brain, these scenarios are equally interpreted as dangerous. In both cases, the body thinks it is starving.
How can it be that weight loss, even if beneficial and appropriate, can be perceived by the body as harmful? Throughout evolution, our bodies have been hardwired with one simple mission: don’t starve. One key hormone at play here is leptin, nicknamed our “starvation hormone,” or our “satiety hormone.” Leptin is released directly from the body’s fat cells to communicate with the part of the brain that controls hunger and eating behavior. At normal levels, it works by inhibiting hunger signals when the body is not in need of energy. This helps prevent overeating, regulating energy-balance systems and promoting weight maintenance.
The largest driver of leptin production is your level of total body fat. The more body fat an individual has, the more leptin in circulation. Extreme caloric restriction or weight loss can cause leptin levels to plummet, leading to a reduction in satiety (decreased feelings of fullness). Leptin works alongside ghrelin, our hunger hormone, to serve as the body’s checks-and-balance in regulation of body weight. A disruption of either hormone can lead to a skewed perception of hunger and fullness and an increased difficulty with weight management.
Aside from body fat, several other factors have a direct impact on leptin production. Large portion sizes (overfeeding) and elevated glucose levels increase leptin production, while fasting and lowered energy states work to inhibit. Additionally, circadian rhythm, sleep, stress levels, and inflammation have a profound role in leptin regulation.
If more leptin means enhanced satiety cues, more leptin should be a good thing, right? Although this logic makes sense, it suffers from several fatal flaws. As with all hormones, the energy-balance system of leptin can be disrupted by the body’s reward system. When you do something that your brain perceives as a survival mechanism (e.g. eat a calorically dense meal), your body sends your brain a shot of the reward-stimulating neurotransmitter called dopamine. The reward system was beneficial for our hunter-gatherer ancestors, when energy demands were high and food was scarce. Today, this evolutionary system doesn’t work in our favor. With constant access to unlimited portions of high-fat, sugary foods, we can easily overeat, which pushes our bodies’ reward system into a feel-good loop.
When we combine excessive portion sizes with hyperpalatable foods, the body has the potential to become “leptin resistant.” With increases in body fat, leptin can be overstimulated, causing our cells to stop responding to the signal for satiety. As such, an overweight individual can feel less full from the same meal as compared to normal weight individuals. These effects can be compounded by poor health and lifestyle behaviors such as irregular sleep patterns, poorly managed stress, and chronic inflammation.
It’s important to remember that leptin is only one factor in weight management and energy-balance. However, diet and lifestyle patterns that promote appropriate leptin function are vital for optimal health. We can help control leptin levels with the following actions:
- Stick to whole foods. Decrease intake of highly processed, energy dense foods that are high in fat, sugar and salt (e.g. pizza, French fries, ice cream, etc). Focus on consuming “real food” - this means consuming eggs instead of a protein bar or almonds instead of an almond flour keto cookie. Removing highly palatable and processed foods from our diet such as added sugars, high-fructose corn syrup, and simple carbs is essential.
- Monitor our overall portion size and caloric intake. Pay attention to hunger and fullness cues, and eat on a schedule that works for you. Regular meal times can help prevent excessive hunger and subsequent overeating patterns.
- Incorporate various methods of fasting. We will dive into fasting more in future education segments, but maintaining at least 14 hours of fasting during the day, avoiding grazing, and minimizing late night eating can help regulate hormone levels.
- Monitor stress levels. Chronically elevated cortisol levels can throw everything out of whack, leading to altered hormone levels, elevated glucose, and increased risk of chronic diseases. Focus on managing stress with regular mindfulness practices and self care.
- Get enough high quality sleep. As previously mentioned, poor sleep habits can alter a whole slew of hormones, leptin included. Prioritize sleep and keep a consistent sleep-wake time.
- Control inflammation. This includes removing pro-inflammatory stimulants (environmental toxins, refined carbohydrates and added sugars, processed foods) and including anti-inflammatory components into your diet (non-starchy vegetables, omega-3 fatty acids, fresh herbs and spices).
Understanding the role of the brain and feedback loops is important for weight management. Controlling leptin production is important, and you can feel empowered that your daily choices can make a significant impact.