When it comes to how much water we should be drinking, there are wide variations in opinions. In all likelihood though, you’re not really drinking enough. Our bodies are made up of about 60% water (1) (2). Throughout the day, the levels in your body decrease. This water is expelled by urine, sweat, and even breathing (1). Average percentages of water in the body do vary according to factors like gender, age, and weight (2). At birth, you start with 50% of your total body weight being made up of water. On average, your body’s level will always remain over 50% (2).
How much should I be drinking?
When it comes to the amount you should be drinking on a day-to-day basis, opinions vary. However, most experts recommend “eight 8 ounce glasses” of water per day. This equates to about 2 liters or half a gallon. Though both Brits and Americans are consuming more water, it’s far below the recommended 8 glasses per day. According to the BBC’s Jessica Brown of Future, most healthy adults have never consumed more than half a pint (240ml or 8 ounces) of plain water in one sitting. But do we actually need to be drinking eight glasses? Well, that’s unclear, but it seems that the likely answer is a resounding no. It’s likely that these recommendations are actually based on a misinterpretation of decades-old information.
But there are experts who claim that it’s necessary to sip on water throughout the day in order to fend off dehydration (1). But it’s likely that, as with most things, it’s personal. Some people may require more than others. It’s also likely that external factors such as the temperature and whether you are sweating excessively play a part. It’s well understood that most people need to consume more during the summer when it’s likely more water is being lost to sweat (2) (3).
Where does the 8 glasses of water rule come from?
It likely stems from a misunderstanding. In 1945, the US Food and Nutrition Board of the National Research Council advised that adults consume 1 milliliter of water per calorie of food (3). For women, this would work out at 2 liters of water per day and for men, 2,5 liters. However, it’s likely that this was based on the fact that most foods contain water already. Meaning it’s unnecessary to compensate and add an extra 2 liters on top of your food. Essentially, all this really entails is eating a healthy and balanced diet. Fruits and vegetables often contain up to 98% water meaning that, if your diet is rich in foods like these, it’s unnecessary to consume the extra 8 glasses (3).
In 1974, nutritionists McWilliams and Frederick Stare co-authored a good called ‘Nutrition for Good Health’. In this book, it was recommended that adults consume “between six and eight glasses of water a day”. However, McWilliams and Stare also noted that this can include “fruit and veg, caffeinated and soft drinks and even beer”. Basically, any drink with a high water content.
Yes, drinking water is good for you
This is, however, not to say that you shouldn’t drink water. The rule of thumb should really be: if you’re thirsty, drink. The body is very good at detecting when it needs what. It’s also important to note that it’s unlikely that you’re severely dehydrated when your body does signal for water. The U.S. National Academies of Sciences, Engineering, and Medicine recommends (1):
- 11.5. cups (2.7 liters) a day for women
- 15.5 cups (3.7 liters) a day for men
However, this includes teas, sodas, coffee, juice, and food.
Drinking more water is proven to help you lose weight and manage cravings. Brenda Davy, a professor of human nutrition, food, and exercise carried out a few studies on this. In one of her studies, subjects were randomly assigned to one of two groups. Both groups were required to follow a healthy diet for three months. One group was told to drink a glass of water 30 minutes before each meal. The participants in the group who drank water prior to eating lost more weight. This can be attributed to the fact that the body finds it hard to tell the difference between thirst and hunger.
Benefits of drinking more water
The benefits of increasing your intake of water are great! There is a definite correlation between drinking more and losing weight. This could be because of the body’s inability to accurately decipher the difference between hunger and thirst. It could also be because, with increased consumption of calorie-free water, you tend to drink less sugary drinks and sodas. And less sugar in the diet will definitely help you lose weight. Research has also found that drinking more water on a daily basis does moderately increase metabolism. It can also help to reduce constipation, increase skin hydration, and reduce the risk of urinary tract infections and kidney stones.
Myths vs Facts
One of the major myths when it comes to water intake is that caffeinated drinks such as coffee and tea don’t count towards your fluid intake (6) (7). This is apparently because caffeine is a diuretic. However, this is completely untrue. Studies have shown that the diuretic effects of drinks like coffee and tea are very weak. Yes, in some people, these drinks may cause increased urination. Overall, however, even caffeinated beverages add to your overall water intake (7).
Overall, adding more water to your diet can only be beneficial. Whether this is done through the consumption of plain water or fruits, vegetables, and other drinks is up to you. Drinking plain water will help you to reduce calories consumed in sugary drinks and thus, is likely to lead to weight loss. Make sure to drink when you’re thirsty and you’ll be fine.