Despite warnings from the government, health groups and doctors, more than 70 percent of Americans still eat too much meat and fat and too few vegetables, cancer researchers said on Thursday.

They published a survey showing 72 percent of Americans still centered their meals around animal fats, leaving little room for the vegetables that prevent not only cancer but heart disease and perhaps a range of other diseases, too.

“Every time we sit down to a meal we are presented with a fresh opportunity to bolster our bodies’ natural defenses,” said Melanie Polk of the American Institute for Cancer Research.

“Today, the overwhelming majority of us routinely squander that opportunity.”

The AICR, which funds research aimed at showing links between nutrition and cancer, commissioned a survey of 1,000 adults. They were asked what they had eaten the night before and how much.

The survey, with a margin of error of three points, showed that only 27 percent were eating the recommended proportion of plant food to animal food.

“This survey shows that Americans have got the proportions of food on their plates reversed. ... Most are cutting themselves off from the protection afforded by the vitamins, minerals and cancer-fighting phytochemicals found in vegetables, fruits, whole grains and beans,” Polk told a news conference.

The U.S. Department of Agriculture, the American Heart Association, the American Cancer Society and many other groups routinely advise Americans to eat a plant-based diet, adding only a little meat and low-fat dairy products.

Even when the people surveyed ate vegetables, they had too few and often the least nutritious kinds, the AICR said. Only 6 percent said they had eaten a salad the night before.

Of those, 19 percent ate salads loaded with meat and cheese.

The AICR also released a study of nearly 30,000 women that showed those who ate a diet closest to the group’s guidelines - rich in vegetables, with moderate alcohol intake - had the lowest risk of cancer.