Young offenders will be given healthy eating advice upon arrival behind bars under new Government plans.
Inmates up to the age of 21 will be provided with nutritional guidance so they can make “informed choices” about their diets.
In another step, canteen stock lists will be reviewed after research suggested over half of food items available for purchase in some establishments were high in fat or sugar.
The measures form part of efforts by the Ministry of Justice to boost the availability of and participation in sport and exercise across the youth justice system in England and Wales.
Ministers unveiled the blueprint as they published the findings of an independent review into physical activity in jails.
The report, by Professor Rosie Meek, said: “Diet and nutrition are not only important features of health promotion, they also have a direct impact on behaviour and mood.”
Items that prisoners can purchase with their own cash must go beyond confectionery, the paper added.
While catered meals provided by the establishment are required to meet basic nutritional guidelines, inmates can purchase additional items known as “canteen” in adult jails and “tuck” in youth facilities.
The report said healthy items are not routinely offered, or when they are, the cost compared to less healthy options is often a barrier.
A review of lists of products that can be bought in public sector juvenile young offender institutions (YOIs) and one young adult YOI showed detainees can purchase from between 185 to 238 items, including condiments, breakfast cereals, snacks and drinks.
Prof Meek’s report said: “After analysing these for sugar and fat content, I found that between 55%-57% of food items for purchase across these prisons were also high in fat, or sugar, or both.”
She recommended that jails should offer nutritional advice as part of their physical activity and wellbeing provision, and promote a readily available range of healthy eating options.
In response, the Ministry of Justice said youth justice establishments will provide information about healthy living and lifestyles during the induction process.
Menus and canteen sheets will be reviewed to ensure healthy options are available and promoted, while young inmates will get nutritional guidance so they can make “informed choices about the amount of fats, sugar and salt that they consume in their diet”.
It comes after inspectors praised YOIs where boys can get sweets as a reward for good behaviour under “incentives and earned privileges” schemes.
In further steps, the MoJ said prison guidelines on physical activity would be reviewed and all young people will be screened by healthcare teams as part of their YOI induction.
However, the department ruled out allowing boxing or martial arts-based activities in jails.
The 100-page independent review also suggested that adult establishments could offer protein supplements, bars and shakes, while “peer-led” yoga or spinning classes could be considered “where appropriate”.
Prof Meek, from Royal Holloway, University of London, said utilisation of sport across prisons and youth custody is “inconsistent and under-developed”, with examples of good practice standing out because they are the exception.
She said: “There is already evidence that sport can have a positive impact on people in custody and I hope that the recommendations outlined in the review will help to improve the lives of people in our justice system.”
Justice Minister Edward Argar said: “This review rightly highlights that sport can help to reduce violence, improve wellbeing and have a positive impact on rehabilitation
“We know that sport on its own does not provide all the answers, but it is a central pillar for helping young offenders to build skills which will ultimately reducing reoffending and help them to turn their backs on crime for good.”