As thermometers rise and the Met Office alerts us to the potential for extreme high temperatures, it is natural to not feel much like eating. Our bodies work overtime to keep our temperature constant, whether the day is cold or warm. Most of the time this is not something you notice, but in extreme temperatures your appetite declines to limit heat-generating processes like digestion of food. This loss of appetite can affect the amount of fluid and salts we ingest.
When we think of hydration, our first inclination is to drink, but food is of equal importance. Here we look at how to balance Hydration in hot weather with sensible eating and drinking.
How do you know if you are dehydrated?
The problem with dehydration is that you are already significantly dehydrated when you experience any noticeable signs. Symptoms such as headaches and fatigue are common when you’re dehydrated. Still, these are late signals as, unfortunately, the body is very good at hiding mild dehydration. It can take quite a few hours before you recognise what is going on. If you are a keen sportsperson, this could have quite an impact as you do not feel thirsty, but your body could be dehydrated. The most essential strategy in all cases is to hydrate regularly.
What are the key signs of dehydration?
The most common signs that you are dehydrated can include:
- Little or no urine or urine darker than usual
- Dry mouth
- Extreme fatigue, mood change and a lack of concentration
- Headaches
- Confusion
- Dizziness
Hydration in hot weather: think about fluids and not water?
Recommending a water requirement is misleading as it is fluid and not just water per se, which is essential. How much fluid a person needs depends on the individual and their lifestyle or environment. For example, someone who lives in a hot country or exercises a lot will require more fluids as their needs are more significant due to sweating.
Pregnant women require more fluid in their diet and it’s older people often experience the uncomfortable effects of dehydration, such as constipation, and this is also the leading cause of falls and fractures, as dehydration can cause dizziness and disorientation.
Most people consider 1.5-2L per day of fluids (the 8-glass rule) to be a benchmark for adequate hydration, but this can come from many different types of liquids and not just water.
Why should you eat your fluids?
Whilst we get most of our fluid intake from water, juices, tea, coffee, and other beverages, according to the British Nutrition Foundation, we get about 20% of our hydration from food, which is why the impact of diet on hydration shouldn’t be overlooked. The accumulation of water from food across the day can soon tally up and offers a valuable source of hydration. Fruits and vegetables are the most hydrating foods, but you can glean fluids from other surprising sources.
What foods have the highest water content?
| Food | Serving size | % water | Water per serving |
| Cucumber | ¼ cucumber (100g) | 97% | 97ml |
| Red pepper | ½ pepper (90g) | 94% | 85ml |
| Broth-based soup | 300ml | 92% | 276ml |
| Watermelon | 100g | 92% | 92ml |
| Tomato sauce | 125ml | 90% | 112ml |
| Milk | 250ml | 87% | 217ml |
| Yoghurt | 150g | 85% | 127ml |
| White fish (steamed) | 140g | 77% | 108ml |
| Eggs | 2 eggs | 76% | 84ml |
| Pasta (boiled) | 180g | 72% | 130ml |
What can you eat for breakfast to hydrate?
During a typical day, you are most likely to be dehydrated when you wake up. During the night, you are still losing water through the skin as sweat and moisture when you breathe and making urine in the kidneys. During the summer, you will lose more water as the higher temperature causes you to sweat more.
Most people start hydrating in the morning with tea, coffee, or juice. You can kick start your hydration with slices of watery fruits such as melon or grapefruit. You can then add hydration with a bowl of cereal and milk topped with berries or yoghurt and fresh fruit. You could also make a breakfast smoothie by adding fruits (fresh or canned) to milk. Try a breakfast salad made of chopped cucumber, tomatoes, red pepper, avocado, and basil topped with an egg fried in a small amount of oil.
What can you eat for lunch to hydrate?
During the summer, there is no end to the variety of salads you can put together to help you to hydrate. Alongside lettuce, add watery vegetables such as cucumber and tomatoes and fruits such as strawberries. Watermelon, cucumber, feta, and mint make a hydrating salad.
Explore hydrating salad dressings made with citrus fruits or vinaigrettes made using berries such as raspberries, which are tasty and hydrating. Yoghurt also has a high-water content to combine with tahini, garlic, lemon juice and herbs to make a hydrating green goddess dressing.
Another hydrating option on a hot summer’s day is a cold soup such as gazpacho. Traditionally this would be made with tomatoes, onion, garlic, cucumber, red pepper, vinegar, and olive oil. However, modern gazpachos use other ingredients, including fruits such as watermelon. The French version is called Vichyssoise and contains potatoes, stock, cream, and olive oil.
Regardless of what you are eating, you can always partner it with a pile of salad vegetables.
How can you eat a litre of water?
| Food | Water (ml) |
| Breakfast: cereal with milk | 180ml |
| Lunch: chicken salad and berries | 390ml |
| Dinner: Spag Bol with jar of tomato sauce and mixed salad | 430ml |
| Total water | 1000ml |
What can you eat for dinner to hydrate?
While you can always eat salad for dinner often, we prefer something hot. Summer casseroles and other one-pot dishes based around stock are very hydrating. You can include meat, fish and seafood in summer casseroles or stick to beans and pulses for something plant-based, but the key is to make them quite soupy with stock.
Tomato-based sauces are also hydrating, and this could be as simple as serving with pasta or a more extravagant seafood dish such as a Creole-style gumbo. Shakshuka is also suitable for something hydrating and nourishing as you cook eggs in a spicy tomato sauce. You could also try cooking mussels in stock and white wine, which is simple to prepare.
Ditch stodgy puddings in the summer in favour of fruit-based crumbles, jellies and even homemade ice lollies made using fruit juice and purees are a good shout.
When the heat rises, prioritising hydration is always a good idea. Always drink plenty of fluids, and if you sweat more than usual due to the heat or exercise, then you can consider an electrolyte (try Healthspan Elite Active Hydrate, £12.99 for 40 tablets). Making food choices based on their water content can also help you hydrate, especially if you are not drinking enough.
For more simple ways to stay hydrated see our Nutrition channel.
About the Author / Rob Hobson
Rob Hobson is a consultant nutritionist working with wellbeing supplement brand Healthspan. Rob also works with private clients and can be found at www.robhobson.co.uk
