So is it bad for your health to eat a lot of fruit? Though a famous study from 1980 argued that based on the evolution of human jaws and teeth, our ancient ancestors used to eat a diet dominated by fruit, there’s not a lot of good evidence for or against fruit-heavy diets for modern humans. “There are some people out there who are fruitarians, and from what we can tell they’re perfectly healthy,” says Dr. Robert Lustig, a neuroendocrinologist and professor emeritus of pediatrics at the University of California, San Francisco. (However, full-blown fruitarianism is so restrictive that it has been linked to nutritional deficiencies in some people, and may be unsafe for children and those with certain medical conditions, like diabetes.)
One critical thing to keep in mind: Drinking fruit juice or fruit-based smoothies is not the same as eating whole fruits, and both of those beverages may pose a number of health risks. Some recent evidence, including one 2013 study from Harvard School of Public Health, has linked fruit juice to an increased risk for diabetes.
See Time Magazine Article 6 Jun 2018