“Listen to your body. It knows what it needs.”
— Anonymous
Have you ever had a day when you could eat almost anything in sight, followed by another when you simply have no appetite?
Sometimes we wake up really hungry. Other days, breakfast is the last thing on our minds.
And occasionally, our appetite changes for no obvious reason. We are sleeping reasonably well, life seems to be going as usual, and yet our hunger feels completely different from one day to the next.
So, why does this happen?
Is our appetite really as unpredictable as it sometimes seems?
And does it work differently for women, men and children?
The answer, as is often the case when we talk about our bodies, is a little more complex than simply saying that we should eat the same amount every day.
Hunger and appetite are not quite the same thing
Although we often use the words interchangeably, hunger and appetite are not exactly the same.
Hunger is mainly a physiological signal. It is the body’s way of telling us that it needs energy and nutrients.
Appetite, on the other hand, is influenced by many more things. It includes hunger, but also our emotions, our surroundings, the smell and appearance of food, habits, memories and even the time of day.
That is why we can sometimes feel hungry without particularly fancying any food.
And at other times, we can have a strong appetite even though we are not physically hungry.
Our brain and digestive system are constantly communicating with each other. Hormones and other chemical signals help regulate hunger, satiety and food intake.
One of the hormones involved is ghrelin, which is often referred to as the “hunger hormone”. Others, such as GLP-1, PYY and CCK, are involved in signalling that we have eaten and helping us feel satisfied.
It is a remarkably sophisticated system, and it is constantly adapting to what is happening inside and outside our bodies.
We don’t need the same amount of food every day
One of the things we sometimes forget is that our bodies do not need exactly the same amount of energy every single day.
Some days we may have moved more, exercised, slept less or simply used more energy than usual.
On other days, we may have spent most of the day sitting, slept well and naturally needed a little less food.
Our appetite can reflect these changes.
This does not necessarily mean that something is wrong.
In fact, expecting ourselves to eat exactly the same amount every day can sometimes make us pay less attention to the signals our body is actually sending us.
This is particularly noticeable in children.
Sleep can change how hungry we feel
Another factor that is easy to overlook is sleep.
After a poor night’s sleep, many of us notice that our appetite feels different the following day.
Sleep deprivation can affect the hormones and brain systems involved in hunger, satiety and food reward.
It can also make highly palatable foods more appealing.
This does not mean that one bad night will suddenly change our appetite dramatically.
But when poor sleep becomes a regular occurrence, it can make it more difficult to interpret our hunger and fullness signals.
Sometimes what feels like an unusually strong appetite may simply be one of the ways our body is responding to tiredness.
Stress can have the opposite effect
And then there is stress.
Interestingly, stress does not affect everyone’s appetite in the same way.
Some people lose their appetite completely when they are worried or overwhelmed.
Others find themselves eating more, particularly foods that provide comfort or are easy to reach for.
This is another reminder that appetite is not controlled by a single switch.
Our nervous system, hormones, emotions, habits and environment all interact with one another.
There may be days when we are genuinely hungry.
Other days when we are simply tired.
And sometimes we may want to eat because we are bored, stressed or looking for comfort.
None of this makes us “bad” at eating.
It simply means that understanding what is behind our appetite can help us respond to it more consciously.
What about women and men?
This is where things become particularly interesting.
It is sometimes said that men have a more stable appetite than women, but there is no simple rule that allows us to say this.
There are biological differences between male and female bodies that can influence appetite regulation, including differences in sex hormones.
For women, hormonal changes throughout the menstrual cycle can influence appetite and food intake.
Some research suggests that, on average, women may eat slightly more during the luteal phase — the part of the cycle after ovulation and before menstruation.
However, the differences are not the same for everyone, and the scientific evidence is not completely consistent.
Some women notice a clear increase in hunger before their period.
Others notice very little change.
And some may experience changes in appetite in the opposite direction.
There is therefore no need to assume that every woman should feel hungrier at a particular point in her cycle.
Our bodies are individuals, not calendars.
And the same applies when comparing men and women more generally.
Sex hormones, body composition, energy requirements and many other factors can influence appetite, but that does not mean that men have a naturally “stable” appetite while women’s appetite is constantly changing.
The reality is much more individual.
Children’s appetites can change dramatically
Anyone who lives with children will probably recognise this.
One day they can eat an enormous dinner and ask for more.
The next day, they seem to survive on a few bites.
It can be tempting to think that they are simply being fussy or that something must be wrong, but children’s appetite can vary considerably as their energy requirements change.
Growth does not happen at exactly the same rate every day.
There are periods when children need more energy and others when their appetite naturally decreases.
This is one reason why looking at what a child eats over time can be more useful than judging a single meal or even a single day.
Of course, persistent changes in appetite or other symptoms should not be ignored. But occasional fluctuations are a normal part of growing.
Should we always honour our hunger?
I think there is something very valuable in learning to listen to our hunger.
For many years, we have been surrounded by diets and rules telling us when we should eat, how much we should eat and what we should avoid.
But our bodies already have an extraordinarily sophisticated system for regulating food intake.
Learning to recognise hunger and fullness can help us move away from constantly trying to control our appetite.
That does not mean that every desire to eat is necessarily physiological hunger.
Sometimes we want food because it looks delicious.
Sometimes because we are stressed.
Sometimes because it is part of a social occasion or simply because we are used to eating at a particular time.
The goal is not to question every bite we eat.
It is simply to become a little more aware of what our body might be asking for.
And when we are hungry, there is absolutely nothing wrong with responding to that hunger with real, nourishing food.
Healthy eating does not mean eating exactly the same amount every day
Perhaps one of the most useful things we can learn is that healthy eating does not have to look identical every day.
Some days we may naturally want a larger meal.
Other days, something lighter may be enough.
Our appetite can change according to our activity, sleep, stress, hormones, growth and many other factors.
That does not mean we need to analyse every fluctuation.
It simply means that we do not have to be afraid of them either.
A varied, nourishing diet based mainly on real food gives us a good foundation for responding to those changing needs.
And perhaps this is one of the reasons why rigid diets can be so difficult to maintain.
They often expect our bodies to behave in exactly the same way every day.
But our bodies don’t work like that.
When should we pay attention to a change in appetite?
Most changes in appetite are temporary and completely normal.
But there are situations in which a persistent change is worth discussing with a healthcare professional.
For example, if we suddenly lose our appetite and it continues for a prolonged period, or if we experience unexplained weight loss, persistent extreme hunger, significant fatigue, pain or digestive symptoms, it is worth looking for the underlying cause rather than simply trying to change our eating habits.
Our appetite can sometimes be an early signal that something else is happening in the body.
And listening to it does not mean being frightened by every small change.
It means knowing when a change is simply part of normal life — and when it deserves a little more attention.
Conclusion: Learning to listen instead of controlling
For a long time, I thought of appetite as something that should remain fairly predictable.
We eat at breakfast, lunch and dinner.
We eat roughly the same amount.
And if one day we are much hungrier than usual, or suddenly have no appetite, we wonder what has gone wrong.
But perhaps our appetite was never meant to be perfectly predictable.
Our bodies are constantly adapting to our energy needs, our sleep, our hormones, our emotions, our activity and even our stage of life.
Children grow.
Women experience hormonal cycles and changes throughout life.
Men’s energy needs also change.
And all of us have days when we need a little more — or a little less.
Perhaps eating well does not mean trying to make our appetite behave in exactly the same way every day.
Perhaps it means learning to listen a little more closely to the signals our body has been sending us all along.
And, when we are hungry, learning to honour that hunger with food that truly nourishes us.
Because healthy eating is not about controlling our bodies.
It is about understanding them a little better.
Glossary
Ghrelin: A hormone involved in signalling hunger and regulating food intake.
Satiety: The feeling of fullness and satisfaction that develops after eating and helps regulate when we eat again.
References
- Tucker, J. A. L. et al. (2025). The Effect of the Menstrual Cycle on Energy Intake: A Systematic Review and Meta-analysis. Nutrition Reviews.
- Darabi, Z. et al. (2025). Appetite-related Gut Hormone Responses to Feeding Across the Life Course. Journal of the Endocrine Society. Review of ghrelin, GLP-1, PYY, and cholecystokinin and their role in appetite regulation throughout the lifespan.
- Coll, A. P., Farooqi, I. S. & O’Rahilly, S. (2007). The hormonal control of food intake. Cell.
- Hirschberg, A. L. (2012). Sex hormones, appetite and eating behaviour in women. Maturitas.
- St-Onge, M.-P. et al. Does sex influence the effects of experimental sleep curtailment and circadian misalignment on regulation of appetite? Review of the effects of sleep curtailment and circadian misalignment on appetite and eating behaviour.