How come some people naturally eat the amount they need, yet for you it’s a real effort? Are they just lucky, or is something else going on? Do you know you overeat, but find it hard to cut back? Have your weight-loss attempts failed because of hunger or food cravings? Perhaps you find hunger such a horrible feeling that you need to eat to get rid of it.
Or maybe you frequently want to reach for food, even when you are not hungry. This could be because the system that regulates your appetite and works to keep your weight constant has been disrupted, so your body is not telling you you’ve had enough. Or another system may have been triggered that drives you to eat, regardless of whether you actually need to.
Julie reckoned she had tried pretty much every diet out there. Each time, she started out full of enthusiasm—hopeful. This time, she would stick to it. She’d buy all the right foods, follow recipes to the letter and do really well the first few days. But then it would start to get tough.
She loved her job as a nurse, but came in exhausted after the night shift and raided her kitchen, often eating crusty white bread slathered with chocolate spread (which she kept in the house only for her son!).
‘Why do I do it?’ she asked me rhetorically. ‘I’m not usually one for sweet foods. Crisps are generally my downfall’. When she was on day shifts, Julie found it easier.
She’d come home and put on music to help her unwind while she cooked dinner. On the days she had choir and book club, she’d have a low-calorie ready-meal before going out.
Julie tried to watch her portion sizes, but had a tendency to reach for food just because it was there. She knew she ate too much, but found it hard to cut back because she then ended up feeling hungry and grumpy.
When we looked at what was going on for Julie, it was clear her appetite-regulation system had been disrupted. She found it hard to adjust her sleep patterns to her work shifts and was lucky if she got six hours’ sleep.
This sleep deprivation was interfering with the hormones that told her when to eat and when she’d had enough. They were out of balance. On top of that, her overly-stressful-at-times job also disrupted her appetite regulation.
Julie admitted that she sometimes ate more crisps than she intended and was shocked to discover that her favorites contained monosodium glutamate (MSG), which can make you want to eat more—though she also felt a bit pleased to hear that there was something in the crisps that triggers overeating and it wasn’t just her! By having low-calorie, ready meals on the days she didn’t cook, she assumed she was being ‘good’.
However, when she checked the ingredients, some of them were high in salt and contained hidden sugars. And they were lower in nutrients than her home-cooked meals. This was not helping her hunger—when our diet is low in nutrients, we experience hunger as more intense and unpleasant. Symptoms might include stomach cramps, tremors, irritability, headaches, weakness and fatigue.
How your body regulates your appetite
There are two systems that regulate your appetite. Your homeostatic system works to keep your body weight constant. Your hedonic system motivates you to find food then rewards you with a sense of pleasure when you eat it.
The homeostatic system
This system works through chemical messengers. Some stimulate your appetite, whilst others suppress it. It is the balance between these signals that regulates your appetite. If you have more of the messengers that increase your appetite, you feel hungrier. If you have more of the messengers that decrease your appetite, you feel less hungry.
Because this system wants to keep your body weight constant, the more excess weight you carry, the more it reduces your appetite. So if this system is working properly, as you gain weight you should want to eat less. Is this your experience? Do you find yourself eating less whenever you gain weight? If your answer is No, this may be because your homeostatic system has been disrupted.
A big cause of this problem is modern diets and lifestyles. With food plentiful and readily available nowadays, if we constantly overeat, we become less sensitive to the signals telling us we have had enough. Many foods (such as white rice, white bread and pasta) are refined, with the fiber removed, so we feel less full.
Monosodium glutamate (MSG), found in some store-bought processed and takeaway or restaurant foods, can damage appetite regulation in your brain, causing you to eat more.4 Other aspects of modern lifestyles, such as stress, lack of sleep and hormone imbalances can also play havoc with this system. Additionally, it can be overridden by the hedonic system.
The hedonic system
When this system is triggered, you will eat even if you are not hungry. The hedonic system worked well at a time when food might be scarce.
And processed foods high in sugar and fat did not exist. Not only do these foods reduce your response to signals that you have had enough to eat, but they also activate the hedonic system, triggering you to eat more.
Ultimately, this may cause changes in your brain that lead to food cravings and compulsive, addiction-like eating. Salty food may also affect your hedonic system, causing you to overeat. It is not just what you eat that disrupts this system.
High levels of stress also affect it, changing your eating patterns and motivating you to eat high-sugar/high-fat ‘comfort’ foods. This can be a bit of a vicious cycle, as these ‘comfort’ foods, in turn, trigger you to eat even more.
Quick questionnaire—Is disruption of your appetite regulation system contributing to your weight?
If you answer Yes to three or more questions, then your appetite may be making it harder for you to lose weight.
Do you find it hard to know when you are genuinely hungry?
Do you find it hard to know when you have eaten a sufficient amount?
Do you often feel hungry even when you have eaten recently?
If you follow a (sensible) diet plan do you feel hungry?
Do you eat more than you need?
Do you sometimes eat (outside of mealtimes), then wonder why?
Do you eat what is on your plate even if you have had enough to eat?
Do you comfort-eat?
Do you eat processed foods or takeaway/restaurant foods that you suspect may contain MSG?
Key things you have learned in this article
You have two systems that control your appetite, your homeostatic system and your hedonic system.
Your homeostatic system works to keep your body weight constant; with this system working properly, the more weight you gain, the less you want to eat.
However, many aspects of modern life can disrupt this system. High-sugar and high-fat foods, monosodium glutamate and possibly salty foods disrupt your homeostatic system, as do stress, lack of sleep, constant overeating and hormone imbalances.
When your hedonic system is triggered, this overrides your homeostatic system and drives you to eat. Stress, high-sugar, high-fat foods and possibly salty foods can be triggers.