Tom Hanks has ruled out taking on roles which require drastic weight gain following his diagnosis with Type 2 diabetes.
The two-time Oscar winning actor has often taken on roles that have required him to manipulate his weight, such as Castaway and A League Of Their Own.
But he told the BBC those sort of roles were 'a young man's game'.
Hanks is in the UK to promote piracy thriller Captain Phillips, which opens the BFI London Film Festival later.
He added: 'I've talked to a number of actors who have gained weight for roles and - just out of the sheer physical toll on one's knees and shoulders - no-one wants to do it again.
TYPES OF DIABETES People with Type 1 diabetes cannot produce insulin. No-one knows exactly what causes it, but it is not to do with being overweight and it is not currently preventable. It usually affects children or young adults, starting suddenly and getting worse quickly. Type 1 diabetes is treated by daily insulin doses, a healthy diet and regular physical activity. People with Type 2 diabetes do not produce enough insulin or the insulin they produce does not work properly (known as insulin resistance). They might get diabetes because of their family history, age and ethnic background. They are also more likely to get Type 2 diabetes if they are overweight. Type 2 diabetes is treated with a healthy diet and increased physical activity.
'I think that's more or less a young man's game. I'm 57 and I don't think I'm going to take on any job - or go on any vacation again - and see to it that I can gain 30lbs.'
'Feeling fine'
The 57-year-old revealed he had been diagnosed with Type 2 diabetes on US TV's Late Show with David Letterman earlier this week.
He told Letterman he had been showing the symptoms for some time.
'I went to the doctor, and he said, 'You know those high blood-sugar numbers you've been dealing with since you were 36? Well, you've graduated! You've got type 2 diabetes, young man.
The actor, who won best actor Oscars for Philadelphia and Forrest Gump, added: 'It's controllable. Something's going to kill us all, Dave,'
Type 2 diabetes affects the body by either not producing enough insulin - the hormone that turns sugar into energy - or by resisting insulin.
People might get diabetes because of family history, age and ethnic background. They are also more likely to get Type 2 diabetes if they are overweight.
Speaking at the Captain Phillips press conference on Wednesday, Hanks said: 'Gaining and losing of weight may have had something to do with this because you eat so much bad food and you don't get any exercise when you're heavy.
'But I think I was genetically inclined to get it and I think it actually and goes back to a lifestyle I've been leading ever since I was seven years old, as opposed to 36.'
The actor added that his diabetes was 'part of life' and that he felt 'just fine'.
Hanks is receiving Oscar buzz for his role in Captain Phillips, which is based on the true story of the 2009 hijacking of the US container ship Maersk Alabama by a crew of Somali pirates.
The film focuses on the relationship between the Alabama's commanding officer, Captain Richard Phillips (Hanks) and the Somali pirate captain, Muse (Barkhad Abdi), who takes him hostage.
Hanks said he met the real Captain Phillips on two occasions and spent several hours with him to find out the 'little details'.
The film's British director Paul Greengrass (The Bourne Supremacy, United 93) said it was a 'great honour and privilege' to have his film opening a festival 'in a city where a lot of movies are made'.
