When we think of ‘hormones’, oestrogen and testosterone are the two which most likely spring to mind, along with their role in puberty, libido and the reproductive system. In fact, our bodies produce a whole host of other hormones which play a part in our health and how we function day in, day out. Ghrelin, given its name as the ‘growth hormone releasing peptide’, controls hunger, food intake and, combined with growth hormone, fat storage.
Stimulated by the cells in our stomach, ghrelin sends signals to the hypothalamus in the brain telling our bodies it’s time to eat. Small amounts are also released by the pancreas and the small intestine. The more ghrelin in the bloodstream, the bigger the appetite and more than likely, the more food you eat. After food, ghrelin levels are decreased because we’re satiated, and they don’t rise again until our body starts looking for more energy.
If you’re trying to lose weight, you might be wondering how you can keep your levels low. To be clear, ghrelin is not bad. Our hormones are made for a reason and they have a very specific job to do in the body. If we weren’t ever hungry, would we take as much joy from the food we eat? How would we know when we’re low on nourishment? How would we function at our optimum level?
It’s when they stop working as they should that we can run into trouble. And our diet and lifestyle choices have a significant impact on this. That doesn’t mean jumping to calorie restriction. Naturally this will increase our ghrelin levels, potentially leading to overeating and storage of fat. Interestingly, research has shown lower fasting levels of ghrelin in individuals who are overweight, obese or morbidly obese, suggesting that over time, overeating can decrease sensitivity to the hormone, meaning we lose this essential control mechanism.
However, it’s important to note that ghrelin may be equally as important in weight gain. It’s all about balance. So I am highlighting a few tips below which will help keep this specific hormone in check and doing its job correctly at both ends of the spectrum.
Eat a diet rich in fibre from fruit and vegetables, legumes and whole grains. Fibre slows down our digestion while also keeping our gut bacteria diverse and healthy. Foods high in fibre also tend to be lower in calories and higher in nutrient density meaning you get a better bang for your buck when it comes to calorie intake.
Limit intake of high GI carbohydrates and processed foods full of sugar and artificial sweeteners.
Refined and processed foods are high in calories and saturated fat and low in nutrients. As well as spiking your blood sugar for a short period, sending your hunger and energy levels on a roller coaster, they trigger the release of dopamine, the neurotransmitter associated with reward. We start to connect that short-lived high with reward as opposed to the feeling of being nourished and satiated.
Eat protein with every meal
Incorporating a portion of lean or vegetable protein into each meal (eggs, oily fish, organic chicken or turkey, tofu, beans and pulses) will slow gastric emptying, keeping you fuller for longer. It will also blunt the insulin spike you get from eating a carbohydrate-based meal, preventing the sugar cravings which inevitably follow that initial sugar high.
Studies in animals have shown that exposure to chronic stress increases circulating ghrelin and growth hormone levels. It also interacts with the brain’s reward pathways to increase food intake, creating a vicious cycle where we begin to see food as a comfort during times of stress and anxiety. Incorporate yoga, meditation or breathing into your daily routine, get out for a walk or run in nature, find something that works for you to allow you to live (and eat) more mindfully.
Sleep deprivation has been associated with an increase in ghrelin levels, appetite and hunger compared to sleeping for longer periods. Aim for 7 to 9 hours per night, practice good sleep hygiene by limiting screen time, avoid heavy meals and alcohol before bed, and try to stick to regular sleep and waking up times to regulate the circadian rhythm.
Research in recent years has shown a link between High Intensity Interval Training (HIIT), reduced ghrelin and increased leptin levels. Incorporate some high intensity exercise into your lifestyle each week – circuits, sprints, cycling. Get out and get sweating!
Massachusetts Institute of Technology. "Ghrelin, a stress-induced hormone, primes the brain for PTSD." 2013 ScienceDaily. ScienceDaily, 15 October 2013. www.sciencedaily.com/releases/2013/10/131015191405.htm>