Though not obese, my 70-year-old father has been overweight for years. I'm concerned about his health. When I or my sister gently point out the need to lose the tummy, he agrees, but does nothing about it. My mother asks him to stop buying treats, then catches him guzzling sugary snacks from a 'secret stash'. He does no regular exercise, is not keen on sport and seems to have no concept of 'cutting back' on cheese, butter and bread. Three years ago his doctor advised him to diet, and for a few months he ate sensibly and lost weight very successfully. How do we motivate him to do so again?

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