You’ve likely heard diets don’t work, or perhaps you have experienced diet failure first hand. Sure, in the short term diets may achieve an initial weight loss, however our bodies are incredible and designed with one chief aim – to keep us alive!

Dieting is the modern day famine/starvation, and activates a range of compensatory mechanisms to ensure precious calories consumed are optimised. Our desire to eat is kicked up a notch in an attempt to gain and maintain body weight within a fairly narrow range (our bodies most comfortable, and often highest weight – this is the set point theory).

When weight loss occurs, part of our brain – the hypothalamus – receives information to switch on compensatory mechanisms. 

Read on to understand how the body compensates and protects against weight loss and why diets fail!


The Hungry Brain

Have you ever wondered why when attempting to reduce calorie intake we feel more hungry, food looks, smells and tastes more appealing? Why do we become more aware and hyperfocused on food around us? (especially foods we might be avoiding!). 

A hungry brain will do everything it can to kick the drive to eat up a notch. 

The Hypothalamus ramps up production of appetite hormones: Ghrelin, GIP, pancreatic peptide.

Ghrelin – think hungry gremlin – is associated with:

  • increased food anticipatory behaviours (that’s thinking about food),
  • foraging and hoarding behaviours (purchasing and/or hiding food),
  • stress-response dysregulated eating (think binge eating episodes),  
  • implicated in memory, learning and motivation
  • associated with anxiety & mood (*hanger* anybody!?)

Whilst the appetite hormones increase, our hypothalamus dials down the fullness/satiety hormones – Leptin, Peptide YY, Cholecystokinin. These are the hormones that signal we are fill/optimally nourished and it’s time to stop eating.

In addition to these hormone changes, hunger also interrupts the way the brain operates and processes – called cognitive changes:

  • Enhanced hedonic response to food (ie. food is EXTRA appealing)
  • Enhanced memory recall of food.
  • Activation of the brain-reward systems to food.
  • Think about, notice and pay attention to food (food fixation).

In addition to these protective efforts, dieting is associated with a range of negative physical and psychological effects. This short blog with infographics details the rarely discussed negative effects of dieting on health.

Bottom line: We don’t fail dieting, our bodies are doing their best to survive and thrive!

Diets fail us.