Many of us forget how brilliantly designed the human body is. And one of its most amazing abilities is the way it knows when it needs fuel and when it needs rest. Indeed, a very complex system of hormones and peptides (proteins) regulates when we feel hungry and need to eat and when we feel full and need to take a break to allow that food to be processed into energy or stored in the body. These hormones and peptides act on specific brain centers to affect sensations of hunger and appetite.
The cycle of hunger and satiety.
In a normal hunger cycle, the brain receives electrical signals from the stomach that it’s empty. These signals—combined with the hormone ghrelin and a neurotransmitter called neuropeptide-Y (NPY)—are activated to stimulate feelings of hunger. When you eat, and the stomach fills up and stretches, it sends signals of satiation to the brain, so that you stop eating, which fire alongside the hormones glucagon-like peptide-1 (GLP-1), cholecystokinin (CCK), and peptide YY (PYY) to inhibit further eating.
Leptin is another important hormone in this process, and it lets the brain know that you’ve filled up on your stores of fat and it’s time to stop eating. In addition, when you eat a meal—especially a carbohydrate-loaded one—insulin is released from the pancreas to stimulate glucose to be used by your body’s cells for energy or put into storage for future use in the form of glycogen. If the glycogen stores are full, insulin will stimulate the glucose to be stored in your fat cells instead.
When your hunger hormones go haywire.
Unfortunately, the Western lifestyle—loaded with sugar and processed foods and lacking in sleep and exercise—can cause this complex system to go a bit haywire, meaning the signals for being full and hungry don’t work. Instead, the system is driven by cravings for sweets or salt and the desire for the emotional relief food often provides. The result is obesity, insulin resistance, and a whole host of health problems. The good news is that there are ways to get these hormones and peptides back under control. The balance and communication of these hormones can go awry with poor lifestyle habits like these:
1. Too many carbs.
Eating too many simple carbs and foods high in fructose causes the pancreas to continuously release insulin. Over time, hyperinsulinemia can occur, which is where levels of insulin are up for so long that eventually the body’s cells become resistant to its effects—leading to insulin resistance. This means blood sugar levels rise and cells don’t get the energy they need, causing hunger, cravings, low energy, obesity, diabetes, and metabolic syndrome. Studies have also shown that eating fructose can lead to higher ghrelin levels, leading to more hunger.
Overeating in general will cause the signaling system to go haywire so that the brain doesn’t know when you're actually hungry. Overeating leads to more fat stores, bigger fat cells, and high levels of leptin that are going ignored and leading to leptin resistance. Leptin resistance means that NPY is going uninhibited, leading to constant hunger and more overeating.
3. Sleep deprivation.
Lack of sleep causes leptin levels to fall and ghrelin levels to rise, and alpha-MSH to fall. Lack of sleep may lead to insulin resistance, diabetes, and inflammation.
4. A sedentary lifestyle.
Lack of exercise leads to poor sensitivity of muscle cells to insulin and less energy utilization, which leads to more fat storage. Stress leads to higher cortisol levels, which inhibits the effects of insulin, raising blood sugar levels, and can lead to more eating and weight gain. You might be able to guess, but this is all about inflammation. Poor food choices, lack of sleep, lack of exercise, and stress increase inflammation, which is associated with insulin and leptin resistance.
Getting control of your hunger.
The key to controlling your hunger cycle is to improve insulin and leptin sensitivity by eating foods that act as fuel, reducing inflammation, and getting your body moving. You can start with the following:
1. Watch your carbs.
Lower your intake of simple carbohydrates. This includes all forms of sugar, fructose, fruit, fruit juice, processed foods, and white flour products. High-fructose corn syrup has been linked to insulin resistance and is found in most processed foods. Stick to one to two pieces of fruit a day. When you do eat carbohydrates, eat them with a food group that will improve insulin sensitivity, such as pickled or fermented foods (pickles, sauerkraut, kimchi) that help good gut bacteria do their job, or use spices like cinnamon or turmeric that aid in metabolism.
2. Eat more protein and other anti-inflammatory foods.
To support your hunger cycle, focus on protein-rich foods from grass-fed meat, greens (which are loaded with magnesium), good fats like omega-3 fish oils, legumes, and fish. Stick to the Mediterranean diet, as it's great at reducing inflammation levels.
3. Get moving.
Up your exercise so that your cells, especially your muscles, are in need of fuel. This will stimulate better insulin sensitivity. And the higher the demand of your muscles, the more improved the sensitivity. Do aerobic as well as anaerobic exercises, including running, jogging, swimming, sprints, interval training, and weight training.
4. Rest your mind.
Get eight hours of sleep or take naps to catch up on your sleep so you can rest your body and your mind. Start a meditation practice, mindfulness training, or adopt some type of stress management therapy to learn how to tame daily stress before it turns into a chronic problem that affects your health.
Want to reduce stress without meditation? Here are some great options.
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Dr. Eva Selhub is an expert in the fields of stress, resilience and mind-body medicine. She studied medicine at Boston University and is board certified in Internal Medicine. She has been a lecturer in medicine at Harvard Medical School, a clinical associate at Massachusetts General Hospital, and was medical director and senior physician at the Benson-Henry Institute for Mind/Body Medicine at the Massachusetts General Hospital. She now runs a private practice as a comprehensive medical specialist and transformation consultant and is the author of Your Health Destiny: How to Unlock Your Natural Ability to Overcome Illness, Feel Better, and Live Longer.