We have all felt that tingling sensation in our stomach launching us into a search mission. A primal switch in our body is turned on, leading us to the cookie jar. It is hard to ignore that call of intense yearning. The six-letter word that you enjoy and dread in equal measure is hunger. It goads you into responding swiftly. It makes you eat.
Have you ever wondered about the mechanism at work in our bodies that prompts this hunger?
Ghrelin is one such hormone that stimulates appetite. It is in fact directly proportional to increased ghrelin levels that contribute to weight gain and obesity. It is produced mainly by the stomach and duodenum in the gastrointestinal tract and is released when the stomach is empty. The hormone has been found to play a role in what is known as meal-time hunger, as well as in the regulation of long-term weight gain and loss.
When researchers discovered that infusing ghrelin into rodents triggers them to eat and leads to obesity as well, it piqued the interest of the scientific community in the role played by ghrelin in human obesity.
Stimulation of Ghrelin
Do you wonder how we are instinctively drawn to food-ordering apps or how we land up in our kitchen when it’s time for lunch? Throughout the course of the day, ghrelin levels waver dramatically, rising steeply before a meal and plummeting after eating. Ghrelin travels through the bloodstream and nudges the brain, which in turn fuels an appetite, slows down metabolism and decreases the body’s ability to burn fat. The hormone also favours the amassing of fatty tissue in the abdominal area. In some experiments, people who got injections of ghrelin before a buffet meal at 30 per cent more than the control group. Results don’t reflect on the scales of some people despite dieting and working out. Higher levels of ghrelin may be at play in such cases.
However, it does not necessarily follow that as a hunger hormone, ghrelin is not good for you. Ghrelin has been linked with maintaining glucose homeostasis during starvation. It has also been suggested by some studies that individuals suffering from anorexia nervosa have elevated blood levels of ghrelin despite compulsive starving. Hunger is not the only factor that determines food intake for people diagnosed with eating disorders. In a study spearheaded by Cano amongst others in 2012 on the role of ghrelin in the pathophysiology of eating disorders, it was found that during refeeding when their calorie intake increased, ghrelin levels drastically reduced pointing to impaired hunger signals in anorexic people.
Some studies indicate that individuals who lose weight by dieting and trying to maintain it makes more ghrelin than they did before losing weight. The body seems to respond by fighting to regain the lost fat. An explanation for these findings is that excess weight may increase sensitivity to ghrelin. So a lower level of ghrelin is enough to trigger hunger.
Leptin
The yang to the yin that is ghrelin is the stop appetite hormone, leptin. It is a hormone produced in the fat cells that play a role in regulating body weight, signalling the brain to reduce appetite and burn more calories. Leptin modulates body weight and metabolism and mediates weight loss. It decreases hunger and food consumption and controls energy expenditure over the long run. But some studies have shown that weight loss causes a marked decrease in leptin levels, which may, in turn, lead to weight regain.
Contrary to perception, obesity is linked to unusually high concentrations of leptin.- Research suggests that some obese people have leptin resistance. Their brain does not respond to leptin, leading to overeating.
Then, although plenty of leptin is produced, the body’s appetite suppression system is unable to function well Changing Ghrelin Levels.
Researchers have discovered a number of behaviours and factors associated with the increase or decrease of ghrelin levels in the body. One behaviour that increases ghrelin levels is not getting enough sleep. Over the long term, getting less than the recommended seven to nine hours of uninterrupted sleep on a regular basis can lead to increased ghrelin levels—which translates into a larger appetite, more calorie intake, and weight gain. In contrast, getting enough sleep every night reduces ghrelin, and thereby reduces appetite. If you snooze, you don’t lose!
On the nutrition front, eating highly refined carbohydrates, especially in the absence of sufficient protein and fibre, can trigger increased ghrelin levels. Protein and high-quality fibre can reduce ghrelin levels to the point that your brain gets the signal that your body has eaten enough. Many people can go on eating chips or a lot of highly refined white bread without the cue of satiety such foods do not contain enough protein or fibre to turn off the ghrelin signals to the brain.
With the intake of refined carbs, your brain does not get the signal that the body has received enough essential nutrients and you tend to continue eating. Usually, with optimal nutrition, ghrelin levels act as a body clock for your meals. They increase prior to mealtime giving you an indication that it’s time to eat and decrease after mealtime.
However, refined carbohydrates can disrupt the process.
Bottom Line
Ghrelin is a gut hormone regulating hunger and food intake. Lower ghrelin levels keep hunger in check. Satiety suppresses it. . Here are a few things you can do to manage ghrelin levels.
- Address the emotions underlying weight extremes: Both obesity and anorexia alter ghrelin levels. Maintaining a consistent weight and avoiding crash diets can help to regulate ghrelin levels.
- Assign importance to sleep: Poor sleep spikes your ghrelin levels and has been linked to increased hunger and weight gain.
- Increase muscle mass: Higher amounts of fat-free mass or muscle are associated with lower levels of the hormone.
- Eat more protein: A high-protein diet increases fullness and reduces hunger. One of the mechanisms behind this is the reduction in ghrelin levels.
- Don’t shun calories: Periods of higher calorie intake can reduce hunger hormones and increase leptin. A study shows that 2 weeks on ghrelin levels were decreased by 18% with 29–45% more calories.
References
- https://www.verywellhealth.com/appetite-regulating-hormones-ghrelin-2509687
- https://www.sciencedaily.com/releases/2021/03/210321215443.htm
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4049314/
- https://www.healthline.com/nutrition/ghrelin
- https://www.nationaleatingdisorders.org/toolkit/parent-toolkit/appetite
