World Water Day: The surprising link between hydration and hunger

World Water Day, observed annually on March 22, serves as a reminder of the criticality of hydration in holistic wellbeing. Considered to be among the most important nutrients, water supports physical functions, including circulation and digestion, supports cognitive function, and helps rid our bodies of toxins. While it is recommended for adults to drink at least 2 litres of water each day, water can also be leveraged as a tool to influence eating patterns, appetite control, and supporting metabolic health.

There is a strong link between hydration and hunger that goes unnoticed by many. People often mistakenly perceive thirst to be hunger and consume additional calories. On World Water Day, nutritionists will help explore the connection between hydration and hunger, debunk common misconceptions about fluid intake, and provide actionable advice on including adequate water in your everyday diet to empower individuals to make informed choices about their water consumption.

How much water should we drink?

“Water constitutes roughly 70 per cent of our bodies. This percentage varies depending on factors including gender, age, and body composition, and so does the quantity of water we should be drinking depending on our lifestyle and diet. While most of us obtain nearly 20 to 30 per cent of water from food, the majority, approximately 70 to 80 per cent comes from beverages,” explains Swati Mohapatra, diet and clinical nutrition, Manipal Hospitals, Bhubaneswar.

She tells us that our bodies cannot store water hence we must ensure that we keep ourselves hydrated. “While the daily requirements vary based on several factors including diet, lifestyle, gender, and age, the adequate total water intake for sedentary adult is on an average between 2.5 to 3 litres per day. To put this in context of body weight, a healthy adult needs around 35 ml of water each day per kg body weight,” she concludes. 

Debunking misconceptions about thirst and hunger

Suvarna Sawant, chief dietician and head of department of clinical nutrition and dietetics at Nanavati Max Super Speciality Hospital, Mumbai debunks most common misconceptions around thirst and hunger:

1. Thirst and hunger originate from different biological signals, yet many people confuse the two.  People mistakenly believe that because they are feeling hungry the body needs food.  In reality, it can also be a sign of mild dehydration.

2. The body has a finely tuned system to keep fluid balance in check, but when a person is caught up in daily activities, thirst can be mistaken for hunger, leading to unintentional overeating. For example, a busy individual might quickly grab a snack rather than pause for a glass of water, thus consuming extra calories when the true need was drinking water. Recognizing thirst correctly can help manage both snacking frequency and total caloric intake.

3. Similarly, feeling thirsty or dehydrated is not the only time when your body needs water. Sometimes, dehydration can happen even when you don’t feel thirsty, especially in individuals living in arid or dry conditions. Thus, drinking proactively is important. 

4. Many people believe that drinking beverages like tea, coffee, juices, is equal to drinking water or keeping the body hydrated. However, these drinks contain caffeine and sugar and fail to achieve the hydration goals, while adding unwanted calories in your body.  It is important to remember that w ater has no substitutes. 

How can we distinguish between true hunger and thirst?

If thirst can be perceived as hunger, then how can we tell the difference? By paying close attention to our bodily sensations. “Common hunger sensations can be a growling stomach, feelings of emptiness or aching in the abdomen. Thirst is regulated by the hormones named aldosterone and antidiuretic hormone (ADH) – responsible for taking care of fluid balance in the body. Thus, thirst symptoms can vary from hunger and include a dry mouth, heaviness, and headaches, coupled with fatigue,” states Vani Krishna, chief nutritionist at Manipal Hospital, Varthur. 

Her advice is simple, “The next time you feel hungry, drink a glass of water and wait for a period of 10 to 20 minutes. If that feeling goes away, it is most likely thirst and not hunger. But if it remains, then it is true hunger.” 

How to leverage water for effectively managing appetite

While there is no ‘perfect time of day’ to get the maximum appetite-control benefit, pre-meal water intake can be of help, according to Sawant. “Observational studies have proved that individuals who drank water before meals, as part of a broader weight-loss effort, experienced more reduction in body weight than those on a similar diet without the added water. This practice, according to the observational findings, may help with satiety and potentially lower calorie intake,” she describes. 

The amount of water an individual should drink is highly variable and depends on considerations related to body size, physical activity level, and other personal requirements. “Drinking half a litre of water before meals is an effective way to manage appetite. Having water before meals fills up the stomach, making the individual feel satiated and thereby bringing down portion size. Water also can temporarily slow down the release of ghrelin, which is the hormone that stimulates hunger when the stomach is empty or when the body needs energy,” suggests Krishna.

Long term benefits of hydrating before meals

“Consistently drinking water could create sustained changes in eating behaviour,” poses Sawant. She tells us of Western studies that have found that people who drink roughly 500 ml of water before meals not only lose more weight but also tend to maintain healthier eating patterns over time. “The results may be subjective and haven’t been scientifically tested in Indian demographic but the concept can translate well to our cultural setting. For instance, having water before lunch might help us feel satisfied with moderate portions, rather than overindulging,” she states.

However, Sawant clarifies, “Such observations do not guarantee automatic transformation of lifelong habits, but they do suggest that including water as a conscious part of mealtime may be easier to maintain than many restrictive diets. Over months, this approach could gradually reshape how much (and maybe even what) you choose to eat.”

Hacks to get yourself to hit your daily water goals

Ask anyone who complains incessantly about hitting their daily water goals, staying hydrated can be a challenge. Here are five practical hacks to ensure you are adequately hydrated throughout the day:

1. The morning glass: Let the first thing you do in the morning is d rink a glass of water. After waking up, drink water to help remove toxins from the body.

2. Infuse your water:  If you are used to sipping on different beverages throughout the day, try adding fruits to your water for extra flavour and hydration. Experiment with combinations of citrus and herbs like lemon, oranges, mint, cucumber, ginger, basil, etc. 

3. Pre-meal water: Drinking water roughly 30 minutes before meals   helps improve digestion.

4. Carry a bottle everywhere: Make sure you always have water handy, especially if you are on the go. High chances are, if you can see it, you will sip on it. You may also opt for a marked bottle with measurements to keep track of your intake.

5. Set reminders: While many smart watches can remind you to move after being sedentary for too long, add reminders for hydration as well.