A little-known Los Angeles physician named Lulu Hunt Peters played a major role in popularizing the use of calorie counting for weight loss. Her 1918 book, "Diet and Health with a Key to the Calories," was the world's first best-selling diet book. Despite the ubiquity of calories today, recent studies reveal that they are an imperfect measure of nutrition. In recent years, there's been a positive trend away from focusing only on calories. Instead, experts are encouraging people to eat more real food — vegetables, grains, lean proteins, and healthy fats.
Read the history and how it developed and changed at http://www.businessinsider.com/calories-not-perfect-nutritionists-say-2017-5