While drinking water can assist in burning calories and curbing hunger, the notion that it directly leads to weight loss is not well-supported by evidence. However, replacing sugary drinks with water can certainly reduce caloric and sugar intake.
The idea that water aids in weight loss has been prevalent for a long time. A 2019 study that took place between 2015 and 2016 revealed that 26.3% of participants drank large quantities of water to lose weight. Although some research suggests a correlation between increased water intake and weight loss, the evidence does not establish a direct cause-and-effect relationship.
Water consumption is linked to heightened sympathetic activity, which affects heart rate and metabolism. This could imply that drinking water might boost your metabolic rate and energy expenditure.
For instance, a 2023 study found that participants who drank 200-250 millilitres (6.8-8.5 ounces) of warm water after each meal lost more weight and had a lower body mass index compared to those who did not. An older study indicated that cooled water increased calorie burn slightly, but the increase was significantly higher with a sucrose drink. This suggests that more research is needed to explore the effects of different temperatures of fluids on energy expenditure.
Substituting high-calorie, sugary drinks with water naturally reduces calorie intake. Some believe that drinking water before meals can decrease appetite. A 2018 study supports this claim but only for individuals with an average weight and body mass index, which leaves its effectiveness for overweight or obese individuals uncertain.
Moreover, a 2016 research suggested that:
Drinking water might help prevent long-term weight gain. A 2013 study reported that the average person gains about 1.45 kg (3.2 lb) every four years. Subjects who added an extra cup of water daily reduced their weight gain by 0.13 kg (0.23 lb), and those who replaced a sugar-sweetened beverage with water cut their weight gain by 0.5 kg (1.1 lb).
A 2019 review found that increased water intake was associated with weight loss ranging from 0.4 to 8.8 kg, with a mean weight loss of 5%. The most significant weight loss occurred when water replaced high-calorie beverages, indicating that water consumption itself may not directly cause weight loss.
Many health authorities recommend drinking eight 8-ounce glasses of water (about 2 litres) per day. Water needs vary based on individual factors such as activity level, sweating, age, and nursing status. It is essential to drink water when thirsty and ensure adequate hydration to avoid dehydration symptoms like dry skin, dark urine, or fatigue.
Typical daily fluid intake recommendations:
These guidelines are general, and individual needs may vary. Consulting a healthcare professional first can provide personalised advice.
A 2021 study involving 45 non-obese participants found that a 5-day water fast led to nearly 5 kg (11 lb) of weight loss. However, unsupervised water fasting can be dangerous and is not recommended by healthcare professionals. The weight lost is likely water weight, and a balanced diet combined with physical activity or exercise is a safer and more sustainable weight loss strategy.
Integrating water into your weight loss journey can be beneficial. It is calorie-free, may increase calorie burn, and could suppress appetite if consumed before meals. Replacing sugary drinks with water is an effective way to reduce sugar and calorie intake. However, there is not enough evidence to suggest that drinking more water directly results in weight loss. Significant weight loss requires a comprehensive plan that includes healthy eating and physical activity, in addition to increased water intake.
