Why Am I Always Hungry? Appetite Regulation and PMOS

You eat a perfectly reasonable breakfast at eight o'clock. By nine, you are thinking about food again. By mid-afternoon you are standing at the cupboard, cross with yourself, wondering how everyone else seems to manage until dinner.

If you have PMOS, previously known as PCOS, this may sound very familiar. Hunger that feels out of proportion, and cravings that are hard to ignore, are among the things women mention to me most often in clinic.

It is tempting to think that you simply need more willpower.

But the research tells a different story. Appetite is regulated by a network of hormones, nerves and brain circuits, and several parts of that network appear to behave differently in PMOS.

So, what is actually going on?

Hunger Is a Biological Signal
Appetite is not controlled by a single hormone, and it is certainly not controlled by a single decision.

Your gut, pancreas, fat tissue and brain are in constant conversation about how much energy has just arrived and how much is in reserve. Some signals rise and fall around meals. Others reflect longer-term energy stores. A region of the brain called the hypothalamus pulls these messages together, while the brain's reward system adds its own opinion about how appealing food looks right now.

PMOS is now understood as a condition involving several hormone systems as well as metabolism. It would be surprising if appetite were left untouched.

Insulin: More Than a Blood Sugar Hormone
Insulin resistance is common in PMOS. When cells respond less well to insulin, the body produces more of it to keep blood glucose in range.

This matters for appetite in a couple of ways.

After a meal that raises blood glucose quickly, a large insulin response can sometimes be followed by a dip in glucose a few hours later. In a study of 1,070 adults wearing continuous glucose monitors, the size of that dip two to three hours after eating predicted hunger, and how much people went on to eat, better than the height of the original peak.

That study was carried out in healthy adults, not in women with PMOS, so we need to be careful about how far we stretch it. But it does offer a plausible explanation for feeling hungry again surprisingly soon after eating.

Insulin is also one of the signals the brain uses to register that food has arrived. Researchers are still working out whether insulin resistance makes that message harder to hear.

Ghrelin: The Hunger Hormone That Does Not Follow the Script
Ghrelin is often called the hunger hormone. It rises before meals and falls once we have eaten.

You might expect ghrelin to be higher in PMOS. In fact, a meta-analysis of 20 studies found that fasting ghrelin tended to be lower in women with PCOS than in women without it, although the results varied widely between studies.

The more interesting finding may be what happens after food. In a small Australian study of overweight women, those with PCOS reported more hunger and less fullness after a test meal than those without, and the researchers concluded that the ghrelin response may be impaired.

In other words, the difficulty may be less about how hungry you are before a meal and more about how clearly the "that was enough" message lands afterwards.

Leptin: Plenty of Signal, Not Enough Response
Leptin is made by fat tissue and tells the brain about longer-term energy stores. In theory, more leptin should mean less hunger.

Several meta-analyses, including one published this year, have found higher leptin levels in women with PMOS than in women without it. Yet appetite does not fall in step. This is often described as leptin resistance: the signal is there, but the response is muted.

It is a useful idea, and it appears to be linked with insulin resistance. It is also still a working theory, not something we can measure and address directly in clinic.

GLP-1: The Fullness Messenger
GLP-1 is a hormone released by the gut after eating. It slows stomach emptying, supports insulin release and tells the brain that food has arrived.

You may have read that women with PMOS make less GLP-1. One small study in lean women with PCOS did find lower levels both before and after a meal. Other studies have found no difference, or even higher levels.

So it is too early to say that PMOS involves a GLP-1 shortfall, whatever social media suggests. I will come back to GLP-1, and to what people now call food noise, later this month.

Why Protein Keeps Coming Up
Of the three macronutrients, protein is generally the most filling. It prompts the release of several gut hormones involved in fullness, including GLP-1.

A review of the evidence suggested that meals containing around 25 to 30g of protein are associated with better appetite control. In women with PCOS specifically, a meta-analysis of eight randomised trials found that higher-protein diets lowered fasting insulin and improved a marker of insulin resistance more than balanced diets with the same calories, even though weight loss was similar.

Protein is helpful, then, but it is not magic. Next week's blog looks at how to build it into meals alongside fibre, fats and enough food overall.

Sleep and Stress Turn Up the Volume
If you read last month's blogs, you will know that poor sleep and PMOS often go together.

When researchers restrict people's sleep, they eat more the next day: around 385 kcal more on average, according to one meta-analysis. The effect on ghrelin and leptin is inconsistent, so changes in food reward and plain exhaustion probably matter just as much.

Stress pushes in a similar direction. A short, sharp stress often switches appetite off. Ongoing stress is different. In a six-month study of adults, higher chronic stress, cortisol and insulin at the start each predicted greater weight gain.

Food Reward: Hunger's Other Half
Not all appetite is about energy.

We also eat because food is rewarding, and some foods are far easier to keep eating than others. In a tightly controlled trial, 20 adults lived in a research unit and ate an ultra-processed diet for two weeks and a minimally processed diet for two weeks. The meals offered were matched for calories, sugar, fat and fibre. People ate around 500 kcal a day more on the ultra-processed diet.

Nobody in that study had less willpower in one fortnight than the other. The food changed, and appetite followed.

The Bigger Picture
None of this means your appetite is faulty, or that nothing can be done.

It means that hunger in PMOS has a physiological basis. Insulin, gut hormones, sleep, stress and the food around you are all part of the picture, and several of those can be supported with practical changes to how you eat and live.

One caution. If you are constantly hungry and also very thirsty, passing urine more often than usual, unusually tired or losing weight without trying, please speak to your GP. Women with PMOS have a higher risk of type 2 diabetes, and those symptoms deserve a blood test, not a new meal plan.

So, the next time you are hungry an hour after eating, perhaps the question is not "What is wrong with me?"

It might simply be: what is my body trying to tell me?

And don't forget, you can always book a free call with us here, if you'd like to discuss further.