Temperatures exceeded 30C (86F) in some parts of the UK in the week of 8 July 2026, the BBC reported on that date1. The report set out guidance from nutrition and food scientists on diet and hydration during hot weather, including the observation that cooking with an oven adds unwanted heat to a kitchen1.
Aisling Daly, senior lecturer in nutrition at Oxford Brookes University, said there is no need for more protein in a heatwave1. The report noted that digesting protein produces more body heat than other food groups, because of the energy the stomach, intestines and liver use to break down and absorb it1. It also stated that cooking a chicken leg in an air fryer uses less than half the energy of a conventional oven, and that slow cookers, though they run for longer, are typically more energy efficient and release even less heat than an air fryer1.
On fluids, the report said the NHS normally recommends six to eight glasses a day, and that in a heatwave a person could need a lot more1. Dr Charlotte Mills, food and nutrition scientist at the University of Reading, said there is no single amount that suits everyone, because fluid needs depend on factors including age, body size, activity levels and health status1. Dr Daly said 80 to 90 per cent of fruit and vegetables are full of water, with cucumber, tomatoes, lettuce, celery, watermelon and strawberries above 90 per cent water content, and apples, carrots, cooked broccoli, pears, oranges, grapes and pineapple at 80 to 89 per cent1. The report gave lower figures for other foods, including boiled eggs at 75 per cent, a cheese and tomato pizza at 38 per cent, takeaway chips at up to 51 per cent and digestive biscuits at 2.8 per cent1. It said pale yellow urine is the colour to look for, and that orangey or dark brown urine is a sign of dehydration1.
The report said warm or room-temperature drinks are just as good as cold ones for cooling down, according to Dr Daly, and that the body is trying to keep its core temperature steady at about 37 degrees celsius1. Dr Daly said one or two coffees a day should make little difference to hydration levels, but five or six will start to have an effect, and the report noted that alcohol also dehydrates1. It also described a southern European pattern of an early breakfast, an afternoon siesta while it is very hot and then a late dinner1.
"As temperatures exceed 30C (86F) in some parts of the UK this week, the last thing people want to do is turn on the oven."
Why it matters for households
The report concerns households across the UK during a week when some areas passed 30C1. Its practical content covers how heat affects appetite and fluid needs, which foods carry a high water content, and how cooking methods add heat to a kitchen1. The NHS figure of six to eight glasses a day is given as the normal recommendation, with the report stating that a lot more could be needed in a heatwave and that individual needs vary with age, body size, activity levels and health status1. Groups the report identifies as needing to drink more include athletes and pregnant and breastfeeding women1. The BBC's Heatwaves and Drought: A Household Guide covers wider household preparation for hot spells, and Why UK Summers Are Getting Hotter and Drier sets out the background to rising temperatures.
What happens next
No further dates or forecasts are given in the report. A related BBC weather article, published on 6 July 2026, reported amber heat-health alerts and the possibility of 10 consecutive days of temperatures over 30C1.
Why UK Summers Are Hotter
