Answer: No doubt the origin of this belief stems from the notion that carbohydrates simply turn into fat, especially carbohydrates that are not being used. However, the fact is the conversion of carbohydrates to fat, a process called de novo lipogenesis, does not occur to any significant degree in people (it does in rodents which is perhaps another origin of this myth). It would first take the glycogen stores in your body to be filled and then consuming 700-900 grams of carbs on top of this over the course of multiple days for de novo lipogenesis to occur at any significant degree as multiple studies have shown.
A final nail in the coffin of this myth came in a study comparing a group who consumed the majority of their carbohydrates in the evening against a group consuming the majority of their carbohydrates during the day with both groups on a caloric deficit diet. The group consuming their carbohydrates in the evening actually lost more body fat and maintained more overall lean body mass than the morning group. The proposed reasoning being the evening group maintained a higher level of leptins. Leptin is a hormone that is synthesized by carbohydrates and is known to signal the brain on the body's current energy status, thus impacting a host of other hormones of significance to the study at hand: thyroid hormones (responsible for metabolism), testosterone (a key factor to muscle growth/maintenance).
Calories Count More
In the end, the timing of macronutrients takes a backseat to overall calories when it comes to fat-burning. People mistakenly believe curtailing carbohydrates intake at night leads to weight loss. However, the reason for the weight loss is mostly likely because of the overall reduction in total calories as a result of eliminating carbohydrates at specific times rather than some special physiological response unproven by science. In other words, as long as your daily carbohydrate intake is not surpassed – aim for about 2 grams per pound of bodyweight – you have nothing to worry about.Kelechi Opara is a lifetime natural athlete with over 15 years experience in the fitness field. He's the creator of the iPhone/Android app Nutritionist, the revolutionary app that's transforming lives around the world. He's also an Optimum Nutrition athlete where he helps in the formulation of their supplements. In addition, he's an internationally published cover model and a former United States Marine.
