When was the last time you had a food craving? You know that feeling when you can’t stop thinking about something sweet at 3pm or a late night snack on a bag of potato chips is too tempting to resist? Have you ever stopped to ask yourself what your food cravings actually mean? Dr Marissa Kelaher explains how our hormones can help, and hinder us.
Part of the reason for those annoying food cravings lies in our hormones - in particular, our hunger hormones. While we’ve been taught to believe that hunger is as simple as calories in and calories out, it’s actually far more complex than we think. Hormones control a huge part of how much we want to eat, when we feel hungry, and even what food we choose (or crave). Leptin and ghrelin are the two main hunger hormones. Leptin makes us feel full and ghrelin makes us feel hungry.
Leptin is made by fat cells, meaning our fat stores affect how much leptin we make.
It’s part of the body’s control mechanism to regulate our weight. Leptin controls hunger, satiety, and even affects our willpower. It speeds up metabolism (via our thyroid) and tells our muscles to burn energy. Leptin also helps immunity and rapid weight loss, or being underweight makes our immune system weaker, making us more prone to infections. Plus, when we lose weight rapidly, leptin levels drop, making it progressively harder to lose more.
It’s why crash diets always fail and we end up often regaining more weight, as our hormones start to work against us. Leptin is also suppressed when we don’t get enough sleep - research shows we eat significantly more calories when we’re sleep deprived. To optimise leptin, getting enough sleep, managing stress, and avoiding crash diets are all key.
Ghrelin does the opposite, it makes us feel hungry and stimulates our appetite. It’s normally released when our body needs more energy, but it’s also released when we see pictures of high calorie food or even imagine this food, which triggers cravings - so don’t shop while hungry. When we eat ultra-processed (junk) food, this stimulates ghrelin release, making us more likely to overeat and think the food we’re eating won’t fill us up. This means ‘diet’ foods often make us feel less satisfied even if they have similar calories. Ghrelin also acts when we are stressed or sleep deprived. Those carb and fat cravings when you’re tired are real!
Ghrelin is suppressed, helping us not overeat, when we eat food we think will fill us up, or eat whole foods (unprocessed - especially high fibre plant foods, these fill us up faster than high fat, high sugar foods) or eat off a smaller plate (this tricks our brain into thinking we’re eating more.) Wait 15 min before going back for a second helping.
If you struggle with overeating or controlling those cravings, remember your hunger hormones and try to use these tips to have a healthier relationship with food - they really do work.
Dr Marissa Kelaher is a GP based at Nelson Family Medicine. She also runs online wellbeing courses via yourlifestylemedics.com. Check out Marissa’s health and wellness tips on Facebook or Instagram @thesimplicitydoctor.
