A new study suggests that pregnant women who indulge on fatty foods can give birth to obese babies.

Researchers from Yale School of Medicine concluded that a high-fat diet during pregnancy can alter DNA structures, impede the brain development of the fetus, and put it at high risk for obesity.

In the experiment, researchers gave pregnant mice a high-fat diet. After giving birth they discovered that its offsprings have an altered hypothalamus, the part of the brain responsible for regulating metabolism.

As a result, these pups are likely to become overweight and develop type II diabetes, compared to the pups delivered by pregnant mice placed on a normal diet.

"It could be a signal to the pup that it can grow bigger as the environment is plentiful in food," said Professor Tamas Horvath, one of the researchers, to BBC News.

"We definitely believe these are fundamental biological processes also affecting humans and influencing how children may eventually become obese. It seems, at least, that this could have a major impact and we need to explore it further in both animal and human studies."

Poor eating habits and nutritional intake are already proven to have negative effects health. It can often lead to obesity, cardiovascular diseases, cancers and osteoporosis.

However, the findings that diet during pregnancy can alter the DNA structure of the fetus is "an intriguing technical advance," said Dr. Graham Burdge, a commenter on the research from the University of Southampton, to BBC News.

Still, he pointed out that the metabolic processes in mice are different from humans, so results may vary.

"Much of what we know about the process comes from animals. The next big thing is to establish the same mechanisms operate in humans and if we can modify that," he added.

The best defense still is to "have a healthy balanced diet and ensure the diet of your child is balanced as well."

This research is published in Jan. 23 issue of the journal Cell.