Little consideration has been given on weight gain by new fathers, perhaps for obvious reasons.
However, the research found that British men put on an average of nearly ten kilogrammes after having a child.
A lack of time to exercise, increased consumption of take away meals and sleepless nights are said to be to blame as pressures mount on the "modern dad".
The study found that 40 per cent of new fathers are unable to pull their weight in the family home because they are so exhausted, the Daily Telegraph reported.
One in ten has to "gear himself up" to rejoin hectic family life at the end of the working day and one quarter admit having to sneak in naps during week days in order to cope. A fifth have fallen asleep while reading to their children.
Paul Keenan of Benenden Healthcare, which carried out the study in conjunction with the Men's Health Forum, said the modern lifestyle was having an impact on fatherhood.
"As we approach Father's Day, we discover that the modern dad's health is suffering under the strain from diverging pressures such as work and family life," he said.
"As a result, dads are taking shortcuts with their diets, leading to increased weight, more sedentary lifestyle and eventually running the risk of health scares."
One in three of the 2,000 fathers questioned said that financial pressures and fears about job stability also played a part.
Researchers warned that the family unit was suffering as a result, with many fathers claiming that they felt too fed up or too tired to play with their children and admitting that they snapped at them as a result of being over worked and under nourished.
Adrienne Burgess, joint CEO of the Fatherhood Institute, highlighted previous research which found that men put on an average of nearly 3 kgs when their partner was pregnant.
"It is largely due to lifestyle as they stay in more. But when a child is born most men, just like the mothers, are running around from morning until night and become far more home-focused," she said.
"It is really up to both parents to make time for the other to get out and go for a jog or go to the gym. Twenty minutes exercise three times a week acts like a mild anti depressant, it's very important," she added.
