Men are three times more likely than women to struggle in telling their partners they need to lose weight.
The finding comes from a survey of more than 2,000 people commissioned by the International Chair on Cardiometabolic Risk (ICCR) to highlight the risks of being overweight, in particular around the belly.
Almost a third of men (31 per cent) do not want to confront their partners about shedding pounds, compared with 10 per cent of women who would not be happy to tell their men to slim down.
But women are much more likely to find it difficult to tell close friends to go on a diet (23 per cent) compared with men (8 per cent).
Abdominal fat around the waist increases the risk of type 2 diabetes, coronary heart disease and stroke. The study, supported by the National Obesity Forum, found 59 per cent of people worried that a loved one with a large waistline would develop serious health problems.
ICCR scientific director Dr Jean Pierre Despres said: “Earlier this year, ICCR found that 41 per cent of Britons do not realise that having fat around their waistline is worse for their health than fat stored elsewhere on the body.
“People need to realise that having excess fat around the waistline, and vital organs such as the liver and heart, can lead to dangerous health conditions.”