Women who do not eat properly in the run-up to falling pregnant could be risking the future health of their children, says a researcher.
28-day foetus: Crucial days for development
Professor David Barker, of the MRC Epidemiology Unit at the University of Southampton, believes that the nutrition the foetus receives in its first days is vitally important.
If mums-to-be do not eat the right things in the build up to getting pregnant, he says, there could be damaging long-term effects.
Much of what is important in pregnancy happens really early
Professor David Barker, Southampton University
Starting to eat properly once a woman finds out she is pregnant may be too late, he said.
Research monitoring the eating habits of 12,000 women in Southampton aged 20 to 34 suggested that 40% were eating an unhealthy diet, he said.
Diabetes and heart disease
He suggested that vulnerability to chronic disorders such as diabetes were set in the womb.
Other studies have suggested that the quantity a baby eats in its first few weeks after birth may influence future risk of diabetes.
Professor Barker presented his findings at a conference in Lyon.
He said: "Much of what is important in pregnancy happens really early - life in the womb establishes the risk for coronary heart disease in later life.
"We're not suggesting anything revolutionary at all in terms of diet but the point is that many young women are not anywhere near getting it right."
He suggested that prior to conception, women needed to eat a diet rich in fruit, vegetables and dairy produce - and not to eat too much meat in relation to carbohydrates.
He said that at least two portions of carbohydrates should be eaten for every portion of meat, and blasted the fashionable Atkins diet, which focuses on high-fat and high-protein foods.