Honestly? We’re overcomplicating stress. Instead of addressing it, we’ve started blaming cortisol. And while the science is complex, the way it’s being simplified is probably doing more harm than good.

Cortisol is the body’s primary stress hormone. Is it directly causing weight-gain on its own? No.

In fact, on release, cortisol helps to mobilise energy, it increases alertness, regulates blood sugar, and supports you to deal with both physical and psychological stress. Short bursts of cortisol are essential – it protects you.

So, the issue isn’t cortisol itself. It’s the chronic elevation of cortisol which can shift how the body stores and uses fat and can make fat loss harder.

Defining “chronic” stress – the persistent, long-term state of tension lasting weeks, months, or longer, caused by unrelenting pressures e.g., financial struggles, unhappy relationships, or intense work environments. Unlike acute stress, it feels inescapable and keeps the body’s fight-or-flight response constantly activated. Chronic stress results in severe physical and emotional issues.

Does cortisol cause increased belly fat?

Here’s the nuance most information misses - cortisol doesn’t create fat out of nowhere – we can’t override basic energy balance; energy must come from somewhere. But cortisol can influence where fat is stored, shifting it toward the abdomen and trunk.

When cortisol is chronically elevated, the research shows a consistent pattern:

• Fat storage is increased around the abdomen (visceral fat).

• The risk of insulin resistance and metabolic dysfunction is increased.

So yes — there is a real relationship. But fat storage cannot work independently of calories.

Why is fat storage increased around the abdomen?

When we talk about abdominal fat, we are not talking about the fat that hides our 6-packs. Abdominal fat – or visceral fat – is metabolically active fat cells, stored deeply in the abdomen surrounding internal organs like the liver and intestines. Unlike subcutaneous fat which is the fat we see and feel under the skin, visceral fat is correlated to increased risk of diseases like heart disease and diabetes.

Side note: although visceral fat is more harmful to health, it responds faster to exercise compared to subcutaneous – which is why exercise is so important regardless of visible physique changes.

Visceral fat is more cortisol-responsive than other fat stores. When cortisol levels rise, visceral fat cells are primed to store fat more readily and effectively than the fat cells located elsewhere in the body.

Visceral fat can also amplify cortisol exposure locally via specific enzymes. The enzyme regenerates active cortisol from inactive cortisone in the fat cells. This creates localised ‘hypercortisolism’ in the abdominal fat even when circulating cortisol levels are normal – further contributing to visceral fat storage.

So - when cortisol is elevated, visceral fat cells are basically more responsive.

Cortisol doesn’t override energy balance.

This is where there can be a misunderstanding. Even in chronic-stress states, fat gain still requires a calorie surplus. Cortisol can change fat distribution and influences eating behaviour – but it cannot not create fat from nothing.

How cortisol indirectly drives fat gain

Where cortisol does have a powerful effect is through behaviour and physiology:

1. Increased appetite & cravings – during periods of stress (both acute and chronic), cortisol interacts with the main hunger hormone, ghrelin. This can increase appetite and food cravings, especially for high-calorie (highly palatable) foods. It seems that the larger the cortisol spike, the more prone to stress-eating and therefore weight gain. The effects can vary with stress type, whether it’s chronic or acute stress, and by individual differences (e.g., obesity, or whether we are an ‘emotional eater’ or not).

2. Blood sugar disruption - cortisol is designed to raise blood glucose during stress. When cortisol is too high for too long, it disrupts normal glucose control and promotes insulin resistance, increasing risk of diabetes.

3. Sleep disruption – sleep loss is strongly linked to higher body weight and obesity. Poor or insufficient sleep tends to disrupt the normal daily rhythm of cortisol especially by raising levels later in the day and blunting the usual morning-to-evening decline. Higher levels of cortisol worsen hunger regulation, increasing hunger, usually leading to increased snacking. More food = higher calorie intake.

4. Muscle breakdown – cortisol is a catabolic hormone for muscle. Chronic elevation can reduce lean mass mainly by shifting protein metabolism, reducing protein synthesis and enhancing protein breakdown. Over time, this loss in lean tissue (and more body fat) lowers baseline metabolic rate.

It’s a feedback loop…

High stress = higher cortisol = more visceral fat = more inflammation and stress signalling… = high stress. And the cycle continues.

What can we do about it?

If cortisol is playing a role body weight, the solution isn’t extreme dieting. The solution is regulation.

Things to focus on:

• Consistent calorie intake – think ‘inclusive’ not ‘restrictive.’

• Resistance training – to protect muscle from breakdown, and to improve insulin sensitivity.

• Sleep quality – to support appetite management and overall wellbeing.

• Stress management – find something that actually works for you because we are all different.

Cortisol is not the problem, but living in a constant state of stress might be.