Chronically underfueling (eating far, far less food energy than you’re burning every day), like very low-calorie diets, can specifically lead to increased visceral fat – the fat stored deep within the abdominal cavity around vital organs like the liver and intestines. This occurs because of the body’s stress response and hormonal adaptations during prolonged calorie restriction.

The Mechanism:

1. Cortisol and Visceral Fat Storage:

   • Chronic calorie restriction activates the stress response, increasing levels of cortisol.
   • Visceral fat has a higher concentration of cortisol receptors compared to subcutaneous fat (the fat under your skin), making it more sensitive to cortisol’s effects.
   • Elevated cortisol promotes lipogenesis (fat creation) and drives fat storage to the visceral area, where it’s more metabolically active and easily mobilized during stress.

2. Metabolic Adaptation and Muscle Loss:

   • Severe underfueling causes muscle loss due to gluconeogenesis—the breakdown of muscle tissue for energy.
   • Reduced muscle mass decreases your resting metabolic rate (RMR), slowing calorie burn and encouraging fat accumulation. Combined with cortisol’s action, the body preferentially stores fat as visceral fat.

3. Insulin Resistance and Visceral Fat:

   • Prolonged stress and calorie restriction can impair insulin sensitivity, partly due to cortisol’s effect on glucose metabolism.
   • Insulin resistance further promotes fat storage in visceral areas, as the body struggles to regulate blood sugar efficiently.

4. Hormonal Adaptation:

   • Very low-calorie diets reduce leptin (the hormone that signals satiety) and increase ghrelin (the hunger hormone), amplifying stress signals in the body.
   • The body responds to perceived starvation by increasing cortisol, which promotes lipogenesis (fat storage), especially in visceral fat tissue (the fat around organs and the belly).

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Supporting Evidence (some of many):

• Study in Psychosomatic Medicine (2000): Researchers found that individuals exposed to chronic stress had elevated cortisol levels, which were strongly associated with increased visceral fat accumulation.
• Research in the American Journal of Clinical Nutrition (2010): Chronic dieting and calorie restriction were linked to increased cortisol secretion, leading to fat redistribution to the visceral region.
• Review in Obesity (2015): Highlighted that stress-induced cortisol dysregulation directly contributes to the accumulation of visceral adiposity, even without significant changes in total body weight.
• A study published in the Obesity journal found that chronic cortisol exposure was linked to increased abdominal fat, independent of overall weight gain.
• Another study in the American Journal of Clinical Nutrition highlighted that calorie-restricted diets can cause significant stress responses, which elevate cortisol levels and impair fat loss goals over time.

Why It Matters:

Visceral fat is particularly harmful because it’s metabolically active and associated with increased inflammation, insulin resistance, and a higher risk of conditions like type 2 diabetes, cardiovascular disease, and liver issues.

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The Takeaway:

While calorie deficits can promote fat loss, extreme calorie restriction causes hormonal disruptions, especially increased cortisol, that favor the storage of visceral fat. A sustainable approach that includes balanced nutrition, adequate calories (a temporary moderate caloric deficit rather than a prolonged excessive one), and stress management strategies is key to avoiding this harmful effect.

We can help!  Reach out to determine the best approach – and amount of daily calories – to ensure your body is fuelled for healthy sustainable fat loss.