Is It Sugar, Carbs, Or Fat?

Nutrition experts have recognized for many years that western diets rich in fats and sugar may be behind the cause of obesity, but debate has reigned over the primary culprit: is it intake of too many calories? Is it specific foods such as carbohydrates or fat? This has led to some groups recommending reducing sugar, some reducing carb intake, while others believe the key is reducing high fat-foods.