10 things you need to know about your Appetite System in order to lose weight

10 things you need to know about your Appetite System in order to lose weight


Many people fail with their approaches to losing weight because they don’t know how our appetite system works.

Here’s what you need to know…


It’s complex

The human appetite system is complex and it evolved over millions of years. What drives us to eat, and what leads us to stop, is an exquisitely orchestrated system of biological and psychological messages that evolved over millions of years. The system was shaped by the imperative to survive in conditions of unpredictable food availability.


We didn’t evolve for our modern food environment

Our ancient evolved appetite system didn’t equip us for our modern food environment.

There’s a tremendous clash between how our appetite system evolved and our modern food environment

  • unpredictable has been replaced with continually plentiful
  • modern foods are energy-dense rather than nutrient-dense
  • soft, easy to chew foods mean it’s easy to eat a lot, quickly, where our ancestors had to do some serious work chewing their food
  • some modern foods stimulate, rather than satisfy, our appetite


We are all different

Like every other human characteristic, we vary in how our appetite works. This shows up early in life – some babies are much more avid feeders than others. Not because they lack willpower (obv!) but because their appetite signalling is driving them to eat more.


It’s a biological system that is affected by our psychology

The system centres on the gut-brain axis, a superhighway of information transfer between different brain centres and our gut. Hormones and nerve pathways offer 2-way communication about our current nutritional status, energy stores and much more.


It’s a psychological system that is affected by our biology

Eating is a behaviour accompanied and influenced by our thoughts (“that looks nice”) and our emotions. Our psychological make-up evolved right alongside our biology, and nowhere is more evident the interplay of attention, motivation, memory and desire than in how we eat. We evolved to seek out food – to hunt and forage – in the interests of our tribe, and we prepared and ate communally.


Our appetite is altered if we develop metabolic disease

Like every other bodily system, the appetite system can become diseased. Non-communicable diseases such as obesity have powerful effects on appetite regulation. If you are living with obesity, your appetite signalling is altered and this in turn affects your psychological expression of your biological drive to eat. Perhaps experienced as continual mental “food noise”, continuous hunger, or never feeling full.


The 10 most important things you need to know


  1. How hunger works

Hunger is your body’s way of telling your brain that you’ve run out of energy from your last meal. Unlike a light switch, it’s not simply on-off. Hunger signals increase in intensity over time, but not in a straight line.

If you don’t eat as soon as you start to experience mild hunger, your gut-brain axis swings into action to release some stored energy. When this happens, those mild hunger signals are switched off. In a while, they will come back, probably a bit stronger this time. This phasic pattern means that tolerating mild hunger is only temporary – the feelings of hunger pass as the energy is released from storage.

This energy release involves burning a tiny bit of fat, so surfing mild hunger without eating means that you are actually losing a bit of weight. It’s important to apply this only to mild levels of hunger – trying to ignore or override stronger signals is likely to backfire and may result in overeating.

  1. How fullness works

You have two types of fullness signals. One results from food entering your stomach. Your stomach is a muscular pouch which stretches as food pours in. Nerve cells in the stomach wall detect this stretching and signal the arrival of food to your brain. Being neuronal signals, these are super-fast.

The second type is the much slower hormonal signals picked up in the gut as food is broken down, absorbed and sent by hormones in the bloodstream. These signals are much, much slower. Maybe 20 or 30 minutes to fully register, compared with seconds for the stomach-stretching fullness signals.

Re-learning to tune in to your immediate stomach fullness makes it much easier to gauge when you’ve had enough. I explain more about how to do this in this video.

  1. There are 3 phases of digestion

Cephalic, gastric (stomach) and intestinal (post-stomach).

The first of these – the cephalic phase – happens in the head. Before even a crumb passes your lips, your stomach secretes acid and insulin release is triggered in anticipation of eating.

When you see food or simply think about it, your body reacts, and you orient towards eating and digesting.

  1. How taste sensitivity works

Famously, “Hunger is the best seasoning”.

This is because our taste sensitivity sharpens as we get hungrier. As we eat successive mouthfuls, this sensitivity dials down so that the later part of a meal isn’t as tasty as the first.

But if we change to a new type of food (dessert, say), we still have an appetite for that, so eating a variety of foods during a meal means we tend to eat more.

  1. Eating for pleasure

“Hedonic” eating is driven by the pleasure centres in our brain. Certain tastes such as sweetness are hard-wired as pleasurable.

The pleasure centres involve positive feedback loops – the more you have, the more you want. Your brain will point you towards seeking out pleasure irrespective of whether you’re hungry or not.

  1. Emotional eating

Food affects our nervous system, and can alter how we feel. If we experience a reduction of a painful emotion when we eat a particular food, or a particular quantity of food, we’re likely to turn to that food again when we feel bad.

The tendency to emotional eating is learned, often early in life. For some of us food becomes our drug of choice to manage emotional pain.

  1. The importance of routine

All of our biological processes are influenced by time of day and circadian rhythms.

Our bodies come to expect food at times that we usually eat, and if we lack a routine to our eating, this important source of regulation is missed, meaning our bodies and minds can’t be sure when food will arrive.

Maintaining weight loss is helped by establishing a regular routine for eating – one that fits your lifestyle.

  1. How much of our eating is habitual

43% of our eating is habitual, meaning it happens on autopilot.

Habits are governed by the subconscious part of our brain, and relatively insensitive to what we intend to do or how we feel today. This means that creating eating habits that you are happy with is key to making weight loss easy to sustain. You want those positive eating patterns to become habitual, so they become your automatic default around food.

  1. How stress affects appetite signalling

The typical response to stress is to go off your food, because of the way stress hormones influence the appetite centres in the brain.

But following periods of chronic stress, this pattern may be reversed so that new stress increases your appetite instead.

  1. The role of anxiety in overeating

Severe food shortage signals mortal danger, so our appetite system is linked to our fear system.

When food is readily available and plentiful, there is no need to feel fearful about feeling hungry, but many of us come to associate hunger with anxiety. Either believing that we can’t cope with feeling mildly hungry, or feeling uneasy if we’re not overly full by the end of a meal can lead to considerable overeating.


Using this knowledge

If any of these 10 points are new to you, learning more about how your appetite system works could be a real game-changer.

My youtube channel has new videos uploaded regularly, about all aspects of the psychology of eating, appetite and weight loss.



Want my help?

If you have tried many times to lose weight but it never worked out in the long run, you should apply for a free Eating Pattern Analysis call with me here:




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