Harvester and JD Wetherspoon have ranked second and fourth in a new league table which exposes the nutritional value of children's menus.
The Soil Association has published the findings in its Out to Lunch campaign which saw secret diners eat in chains around the country after 66 per cent of parents said they don't think kids' food in restaurants is good enough.
This year's clear winner was Jamie's Italian which received a score of 64 (up from 50 two years ago) out of 80 for its children's picnic boxes and organic mini spaghetti and meatballs, followed by Harvester (45 points), Giraffe (44) and Wetherspoon (43).
Contrary to popular belief, healthy meals are not more expensive as the average meal price for eating out with children is £5.61, and the top five healthiest chains' average meal price is £5.55.
Rob Percival from the Soil Association said: "Our 2015 league table includes big winners and big losers - adults expect to be offered real food and real choices in restaurants and we think children deserve the same.
"We've found some up-market eateries are designing menus that make healthy eating for children almost impossible, and price is no guarantee of quality - lower cost restaurants are outperforming more expensive chains. Since our first league table Harvester and Prezzo have proved it's possible to make major improvements – we're now calling on other restaurants to raise the bar and give our kids the food they deserve."
The campaign found that restaurants were serving potatoes pre-mashed in Holland, fish fingers pre-cooked in Poland and one chicken product had 19 additional ingredients produced in Kazakhstan, Russia, Vietnam, Argentina, Malaysia, India, Singapore, Indonesia, China, Ukraine and Slovakia.
Additionally, more than half of the restaurants gave no indication of where the food came from, and only Jamie's Italian could reliably tell parents where the meat came from.
One of the secret diner parents, Kate Blincoe, said: "I really care about what my children eat, but as secret diners they were served up with vegetable-free meals, sugar-laden deserts, and they had to eat with adult cutlery. Overall, there is a lot of work to be done to make eating out with kids healthy and family friendly, and I was particularly shocked by where the meat came from in the restaurants we visited."
The first league table was produced two years ago and since then, the campaign has worked to help chains improve the nutritional values of their children's menus.
Out to Lunch's 7 steps to improve children's food and service
1. Make water freely available and remove sugary drinks from the menu
2. Let children choose from the main menu
3. Serve a portion of veg with every meal and fruit-based puddings
4. Use quality ingredients such as free range and organic
5. Provide children's cutlery as standard
6. Serve freshly prepared food, not ready meals
7. Make breast feeding mums feel welcome