While women diet to feel better about themselves, men are more focused on losing their love handles to spice up their sex lives, according to a survey carried out for supermarket giant Tesco by polling firm YouGov.
Of the 2 000 people surveyed 20% of men admitted to being on some kind of diet every month to get trim for the ladies, with 10% of them believing a trimmer figure would add sparkle to their bedroom performance.
Out of the women, 60% said they counted the calories hoping to boost self esteem.
Women are so concerned with their widening waistlines that one in 20 admitted to spending more than three hours a day just worrying about their weight.
Psychologist Donna Dawson says a long-term healthy lifestyle will be much more beneficial than trying out many different fad regimes.
"It is important to understand that constant yo-yo dieting which is doomed to failure will only serve to undermine self-confidence," Dawson said.
"Silver slimmers" – people over 55 years old – are the most likely group to be relentless calorie-counters. Fifteen percent said they restricted the amount of food they eat every day, double the number of any other age group.
The obsession with dieting does not appear to be translating into a trimmer nation.
A government report into rising obesity levels has predicted that 60% of Britons will be overweight by 2050, up from 28% in 2007.