Pensioners who wear themselves out digging in the garden should eat steak and drink orange juice in a bid to keep themselves fortified, according to research.
A study claims that many older people are not getting enough protein to keep their muscles strong and nerves healthy.
Research showed that combining low-level exercise with a body-building supplement dramatically improved the fitness of volunteers aged between 65 and 92.
Carbohydrates, available in glucose drinks and fruit juice, were also necessary to provide energy, according to scientists.
Dr Gladys Pearson, from Manchester Metropolitan University, said: "Our advice is to have a glass of orange juice before doing the gardening, and half an hour afterwards a steak or some other kind of protein-rich meal because this is the time when the body is ready and raring to take up protein."
Speaking at the British Association Festival of Science, Dr Pearson said a healthy dose of proteins was 0.8 milligrams per kilogram of bodyweight.
Boosting proteins and carbohydrates helped to reduce biological processes leading to inflammation and muscle loss. However, these adverse effects were increased when older people tried to do too much exercise, Dr Pearson said.
Insufficient protein after exercise causes the body to break down muscle instead of building it up.