Have you ever heard the saying: ‘you aren’t hungry, you’re just thirsty’?⁣

This is often recommended as a weight loss strategy, therefore today, we explore whether this statement is true or not.⁣
In other words, does your hydration status affect hunger and your desire to eat? And if so, does drinking more water reduce appetite and help calorie management better?⁣

McKay et al (2018) put this hypothesis to the test through two experiments…⁣

Experiment 1:⁣

Forty-nine individuals were preloaded with either one, two or three 500mL bottles of water in the morning before a buffet style lunch.⁣
As the hypothesis would suggest, those who drank three bottles vs one consumed less food at the buffet – but only in those classified as ‘normal weight’.⁣

Out of the possible 3,800kcal on offer, the hydrated-normal weight individuals consumed 945kcal vs 1119 and 1120kcal: approx. 250kcal less.⁣

However, those who were defined as overweight/obese, preloading with three bottles of water before heading to the buffet had no effect on appetite control.⁣

All participants regardless of BMI consumed the same amount of water (not relative to bodyweight) – therefore, they further hypothesised that the smaller healthy weight individuals were more hydrated which impacted intake.⁣

Experiment 2:⁣

In a follow up study, 45 individuals further increased water intake to 4x500mL bottles before hitting the buffet – this time, preloading with water had no effect on hunger management in either healthy weight or overweight/obese.⁣

Interestingly, both hunger levels and food liking scores decreased as they became more hydrated – but didn’t impact actual calorie intake.⁣

This study certainly had a few limitations, but overall would suggest that water-mediated suppression of hunger gives individuals the impression they are going to eat less, but this unfortunately isn’t the case, and if so, only in certain circumstances.