Not drinking Enough Water May Lead to Obesity

I previously wrote an article titled “Losing weight is as simple as drinking water, literally!” about a study that showed that you can lose weight by drinking at least 2 cups of water half hour before meals. Now research shows that not drinking enough water may actually lead to obesity. The study was published in Annals of Family Medicine. Lets look at the results.

Large Study of US Population

Researchers used a nationally representative sample from the National Health and Nutrition Examination Survey (NHANES) 2009 to 2012, and included adults aged 18 to 64 years. The primary outcome of interest was body mass index (BMI) and also categorized as obese (BMI ≥30) or not (BMI <30). They measured urine osmolality, a measure of how concentrated the urine is which is an indirect measure of hydration levels. Urine osmolality is used in this study as it is a better indicator than just water intake because it accounts for water and solutes acquired in food and other drinks. Values of 800 mOsm/kg or greater were considered to be inadequately hydrated.

Less Water Intake, More Weight

The study showed that adults who were inadequately hydrated had a mean BMI of 1.32 kg/m² more than hydrated individuals, on average. The odds of being obese were 1.59 times higher for inadequately hydrated individuals compared with hydrated.

Hydration Helps to Curb Obesity

The authors note that clinicians may not be aware that people with higher BMIs need more water, and they may not be properly counseling them on hydration amounts.

“Obese individuals have higher water needs than non obese individuals, because water needs depend upon metabolic rate, body surface area, and body weight,” they explain.

The authors also add that poor hydration has also been linked to worsened mental, physical, and emotional health, and it may affect performance in tasks that require attention, psychomotor, and memory skills. Declining mood, headaches, and poor kidney function have also been linked to inadequate hydration.

Correlation But No Causation

The study showed a correlation of poor hydration levels to more obesity. But it does not prove that poor hydration can actually cause the obesity. Until we have more studies, it does not hurt to drink lots of water, unless you have heart or kidney issues.