Ghrelin: The Hunger Hormone

 

Have you ever wondered what is happening in your body to trigger that feeling of hunger? One of the processes at play involves a hormone called grehlin.

Ghrelin is known for regulating our appetites, but it also affects stress response. Understanding how it works and what you can do to keep it in balance can help you feel more in sync with your hunger cues, especially when life gets intense.

What Is Ghrelin and What Does It Do?

Ghrelin is often called the “hunger hormone.” It’s produced primarily in the lining of your stomach, with smaller amounts also released by the small intestine, pancreas, and brain. It travels through your bloodstream to your brain, where it tells the hypothalamus: “Hey, it’s time to eat.”

Ghrelin levels naturally rise before meals, which helps trigger that familiar “I’m hungry” sensation. After you eat, ghrelin levels fall. But not all foods have the same effect on that drop (more on that soon).

In addition to hunger signalling, ghrelin also plays roles in:

• Stimulating appetite and increases food intake (by up to 30% when administered in studies)
• Acting on the rewards centres in the brain (like the amygdala)
• Regulating energy balance
• Stimulating the release of growth hormone from the pituitary gland 
• Influencing insulin and glucagon release from the pancreas
• Interacting with the stress-response system (HPA axis)

Ghrelin and Stress: A Fast-Acting Response

A paper that included a meta-analysis of 10 studies, showed that ghrelin levels increase in response to acute stress, usually within five minutes of the stressful event.

Researchers tested this using stressors like:

• Public speaking under pressure
• Cold water hand immersion
• Treadmill sprints to exhaustion

This short-term spike in ghrelin may be an adaptive response, your body’s way of preparing for action, or trying to restore balance. Interestingly, ghrelin also seems to help modulate the stress response itself by interacting with your HPA axis - a communication loop between your hypothalamus, pituitary gland, and adrenal glands. It’s your body’s central stress-response system, responsible for releasing cortisol and other stress hormones when you’re under pressure.

Different nutrients suppress ghrelin to different degrees:

• Protein and carbohydrates reduce ghrelin more effectively than fats
• Somatostatin (another gut hormone) can also suppress ghrelin.

What’s especially notable is that people with higher BMIs tend to have a bigger and longer-lasting ghrelin spike in response to stress. In some individuals, this can drive stronger cravings and potentially increase the risk of stress-related overeating.

Can You Measure Ghrelin Levels?

Technically, yes — but not in a way that’s practical for everyday health tracking.

Ghrelin is measured through blood tests in specialised labs, often as part of research studies. It’s not something your GP can check with a standard blood panel, and it varies rapidly throughout the day.

The good news? You don’t need to measure it directly to support healthy ghrelin function. There are simple, evidence-backed habits that help your body regulate it naturally.

How to Support Healthy Hunger Signals (Without a Lab Test)

If your hunger cues feel out of whack (either constantly high, or hard to detect) there are a few ways to help bring things back into balance:

🥦 1. Prioritise protein and fibre

Both protein and fibre-rich foods help blunt the post-meal rise in ghrelin more effectively than high-carb, low-protein meals. Why?

• Protein slows digestion and supports satiety hormones like peptide YY and GLP-1.
• Fibre (especially soluble fibre) adds bulk and slows the rate at which food exits your stomach, helping you stay full longer.

Together, they lead to a more gradual and sustained drop in ghrelin, helping your body feel fed and satiated.

Try: A Roam protein smoothie with fruit and nut butter.

⏰ 2. Eat at consistent times

Your ghrelin rhythm follows a kind of internal clock. If you eat erratically, ghrelin can surge at odd times, even when you don’t need the energy.

Eating at regular intervals helps train your body to expect food, which can lead to more stable hunger patterns and fewer surprise cravings.

Try: Planning meals at roughly the same time each day, even on weekends. 

😴 3. Prioritise quality sleep

Lack of sleep has been shown to increase ghrelin and decrease leptin (the hormone that tells you you’re full). This one-two punch makes you hungrier and more likely to crave high-sugar or high-fat foods.

Even a few nights of poor sleep can throw your hunger hormones off. Over time, this can lead to energy dips, weight gain, or poor recovery from training.

Try: Aiming for 7 to 9 hours of consistent, high-quality sleep, especially if you're training regularly.

🚶4. Stay physically active (but not burnt out)

Regular movement supports long-term appetite regulation and can help your body respond more steadily to hunger and stress.

Some people find that intense training temporarily blunts their appetite. This isn’t necessarily a bad thing; the key is avoiding overtraining without adequate recovery, which can throw off hormones like ghrelin over time.

Physical activity improves insulin sensitivity, boosts mental wellbeing, and supports more stable energy levels.

Try: Mix of movements that you enjoy: running, walking, hiking, strength training, yoga, or high-intensity sessions balanced with proper rest.

Ghrelin is a powerful hormone with a lot going on behind the scenes. It rises before meals to help you feel hungry, but it also responds to stress, and that response is stronger in some people than others, particularly in those with higher body weights.

You don’t need to track it or test it. But by prioritising real food, moving your body, and getting enough sleep, you can help your system stay balanced.

At Roam, our gut-friendly proteins and energy nut butters are designed to keep you fuelled and satisfied — no crash, no guesswork. Just good food that works with your body.