Nutritionist Dr Federica Amati has challenged the long-held belief that everyone should drink two litres of water a day, stating that for most young healthy people, hydration is not an issue. In an Instagram post, she explained that listening to your body's thirst signals is the most effective way to maintain hydration, rather than striving for a specific daily target.
NHS Advice vs. New Guidance
The NHS advises drinking six to eight cups or glasses of fluid each day, including water, lower-fat milk, sugar-free drinks, tea, and coffee. However, Dr Amati argues that the 'two litres a day' rule is not necessary for everyone. She noted that hydration becomes more of an issue for people who are sick or elderly, as their thirst response is dampened with age.
Rehydration Salts: Use with Caution
Dr Amati cautioned against regular consumption of rehydration salts, which can contain high levels of sodium, a risk factor for hypertension. She recommends using them only after intense physical activity, such as completing a marathon or sweating heavily for several hours.
Water from Food
She reminded the public that a significant amount of water intake comes from food, particularly whole fresh fruits and vegetables, which contribute to hydration levels.
How Much Water Do You Really Need?
An expert from Nuffield Health provided a more personalised guideline: aim for around 35ml of water per kilogram of body weight. For example, a person weighing 72kg (159lbs) should target roughly 2.5 litres daily; 85kg (188lbs) about 3 litres; and 100kg (220lbs) around 3.5 litres. Additional water may be needed for physical activity, exercise, or hot conditions.
Risks of Over- and Under-Hydration
The Nuffield Health expert warned that drinking too much water can lead to loss of valuable minerals like salt and potassium in urine, while drinking too little can cause minerals to crystallise and form kidney stones. Proper hydration is crucial for supporting health, vitality, and overall well-being.
