Dr Lockwood, from IVI Midland, in Tamworth, said she now advised all patients to go “low carb”.
“They should be eating plenty of fresh vegetables and protein and limiting their carbohydrate intake to just one group and portion a day.
“I tell my patients that if they are going to have toast for breakfast, then that is their carbs for the day. They cannot then have a sandwich for lunch and pasta for dinner.
“If they want a pasta supper that has to be their carb, or if they want a jacket potato for lunch, then that is it.”
Women were also advised to eat dairy foods as cholesterol is the ‘building block’ for all the reproductive hormones, she said.
Today’s typical diet was storing up fertility problems, she said.
“Modern food is very carb-rich, tasty and cheap, so it’s easy to see why people tend to eat a lot of this food. But it is also very low in nutrition,” she added.
“The women’s partners also need to do their part and scrap their stuffed-crust pizza and enjoy a chicken salad too,” she said.
Speaking at the European Society for Human Reproduction and Embryology conference in Geneva, British fertility experts said they have just begun diet clasess for infertile couples, in a bid to improve their chances.
Leeds Fertility last month began giving infertile couples four lessons in nutrition – including cookery classes, to encourage them to cut the carbohydrates, and introduce a more varied diet.
Grace Dugdale, the reproductive biologist leading the scheme, said couples trying for a baby should cut out all white bread and pasta, and switch to wholemeal versions.
She suggested replacing processed breakfast cereals with eggs, or natural yoghurt and fruit, and advises swapping lunchtime sandwiches with carb-free salads. When carbohydrates were consumed, unprocessed was best, she said, recommending muesli and porridge over sweetened cereals.
Couples should try to stick to just one portion of carbohydrates a day she said – and make it a complex one, such as brown rice or wholewheat pasta.
Miss Dugdale said: “People should be cautious of the refined carbohydrates in white bread, pasta, cereals, biscuits and cakes because their simpler molecules break down more quickly in the body, causing a spike in blood sugar.
“Over time the body becomes less able to process sugar, leading to poor metabolic health, which can cause inflammation in the body and damage mitochondria, the powerhouses of the cells.
“A woman’s eggs are very large cells with a high number of mitochondria, so their quality is affected. Poor diet that includes refined carbohydrates can also affect male fertility by damaging the DNA in sperm. This affects sperm motility, their ability to swim, their morphology, or the shape which makes them good swimmers, and the sperm count, or how much sperm is produced.
“A diet low in refined carbohydrate is therefore important for both the man and the woman.”
The scheme led by Balance Fertility, a research company looking at lifestyle and underling factors behind infertility, will be expanded in September, with patients getting individual consultations to look at their diet and lifestyle in detail.
Prof Adam Balen, chairman of the British Fertility Society, said all couples could give their fertility the best chance by eating a healthy diet, and looking in particular to cut carbohydrate levels.
He said: “We know that diet has a major impact on chance of conception and on egg quality and increasingly it seems that carbohydrates play a particular role.”
And he said those struggling with fertility problems should undergo individual consultations to check levels of key nutrients, vitamins and minerals.
The British Dietetic Association said further research into the area was needed. A spokesman said: “As dietitians we don’t promote demonising nutrients, but paying attention to diet, encouraging moderation and portion control both pre and during pregnancy are extremely important for mum, dad and baby.”