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Why am I hungry all the time? We explain the science behind appetite regulation.

Updated: Aug 30, 2021

Let’s face it, when we’re feeling hungry (or full) we rarely question what’s actually happening inside of us to make us feel that way. In this article, our associate Nutritionist, Joesph, talks us through the science of appetite regulation and helps to educate us as to why we feel full or hungry and gives us some handy tips on how to stay fuller for longer.

How do our bodies control appetite?

Appetite regulation is the system that governs appetite, which means the processes taking place in our body that result in us feeling hungry or full. This is an extremely complicated and integrated system which regulates around 1 million calories our bodies consume throughout the year (1). Even when a little weight is gained throughout this period, it takes an incredibly efficient system to perform such a balancing act of calories in and calories out.

How does our appetite regulation system work?

The role of our brain

The brain is important in this appetite regulation system, especially a section that’s so deeply ingrained called the hypothalamus. The hypothalamus is the feeding centre and is responsible for numerous different homeostatic processes, one such process is keeping our body in a balanced state - like feeding and fasting for example. The hypothalamus releases different hormones to make us feel full or hungry (2). These signals depend entirely on what’s happening lower down in the body, our gut!

The role of our gut

Throughout the gut are cells called enteroendocrine cells which sense the environment and then send a message to the brain to release an appetite-stimulating hormone or an appetite-suppressing hormone (3). After indulging in a breakfast buffet, for example, these cells will sense the large volume of food consumed and signal to the brain to suppress appetite. Or, after a day without eating, these same cells will release a hunger hormone to signal to the brain to feel hungry and consume food.

When losing weight or simply trying to take our mind off food, staying full and satisfied is essential. Let’s take a quick look at some of the tricks we can do to feel more full throughout the day.

Food choices that help us stay fuller for longer


Fibre is the structure for plant-based foods and is indigestible, which means we can’t digest fibre and use it for energy - it contains no calories. It is found in numerous plant-based food groups, and you’ll find the highest quantities of fibre in:

Non-starchy vegetables: spinach, kale, broccoli, asparagus

Seeds & nuts: flaxseeds, chia seeds, almonds, cashews

Beans & pulses: lentils, black beans, chickpeas

Research has shown these enteroendocrine cells receive signals from fibre to release hormones that signal to the brain to make us feel more full (4). Although the exact quantity of fibre needed to produce these effects isn’t yet known, there does seem to be more and more evidence highlighting its appetite suppressing qualities.

Protein Protein is an essential part of a healthy balanced diet and you may be aware of its role in muscle recovery, but it’s also quite a potent appetite suppressor too! Protein is digested more slowly compared to carbohydrates, a process termed ‘delayed gastric emptying’. It has been shown to elevate hormones that suppress our appetite, leading to increased feelings of fullness (5). High-quality protein sources include:

  • Meat & poultry

  • Fish

  • Dairy

  • Tofu

  • Legumes


Research has shown on numerous occasions that exercise, especially endurance-type exercises like running and cycling reduces our hunger signals. This means after your run in the park you’re not only getting numerous other benefits from exercise, but you’re also decreasing your appetite signals too (6).

This is an exciting area of research and we’re steadily beginning to understand exactly what is taking place when we’re feeling hungry and full. If you’re looking to lose weight, controlling appetite is essential.


Joseph, specialises in appetite regulation, weight loss and personalised nutrition. He is our associate nutritionist with the AfN & also works as a health coach looking at lifestyle factors that influence eating behaviours. Please contact us to request Joseph's expertise.

References for further reading:


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