Recipes by TV chefs including Jamie Oliver and Nigella Lawson are "less healthy" than ready meals, researchers have said.
Meals randomly selected from the books of top TV chefs contained "significantly more" fat, saturated fat, energy, protein and less fibre per portion than supermarket ready meals, the study suggests.
Neither the ready meals or the recipes complied with all of the nutritional recommendations by the World Health Organisation (WHO), the study suggested.
Every year, UK residents spend £2.5 billion on ready meals - which are often portrayed as being unhealthy. Meanwhile, many people's diets are influenced by recipes created by popular TV chefs - which are "sometimes promoted as being healthy".
Researchers from NHS Tees and Newcastle University decided to compare the nutritional content of the meals. In December 2010, researchers chose the top five TV chef recipe books on amazon.com, including 30 Minute Meals and Ministry of Food by Jamie Oliver, Baking Made Easy by Lorraine Pascale, Nigella Lawson's Kitchen and River Cottage Everyday by Hugh Fearnley-Whittingstall.
They compared the nutritional content of 100 recipes randomly selected from the books to 100 own-brand ready meals from Tesco, Asda and Sainsbury's. The study, published in the Christmas edition of the British Medical Journal on bmj.com, found that no recipe or ready meal met all of the WHO nutrient intake goals for preventing diet-related diseases.
"Meals based on television chef recipes were less healthy than ready meals," the authors wrote. "Significantly fewer were within the recommended ranges for fibre density and percentage of energy derived from carbohydrate and fat, and per portion they contained significantly more energy, protein, fat, and saturated fat and significantly less fibre."
The authors suggest that TV chefs who create unhealthy meals should be subjected to a 9pm watershed. They also state that recipe books should contain more nutritional guidance, such as those portrayed on the front of many food products.
A spokesman for Jamie Oliver said: "We welcome any research which raises debate on these issues and in fact Jamie's most recent book, 15 Minute Meals, does contain calorie content and nutritional information per serving for every dish. We will soon also be re-launching the Jamie Oliver website with nutritional information on the recipes. However, we would regard the key issue to be food education so that people are aware of which foods are for every day and which are treats to be enjoyed occasionally."
A spokeswoman for Lorraine Pascale said: "Some of the recipes in Lorraine's book are healthy, some not quite so much so. There are plenty of salads, soups and light meals as well as the richer dishes. Her books and shows to date haven't been about healthy eating, they are about cooking. However, funnily enough, the topic of her next series and book specifically addresses healthy eating."