MORE DEBUNKING OF FITNESS MYTHS - I LOVE IT! “Carbohydrates make you gain weight.” This is one of the many diet myths that abound these days, fueled by food marketing and the diet industry. But what’s really behind these myths? The simplest explanation is usually closest to the truth, and this applies to nutrition, too. When it comes to healthful eating, the key to success is to eat fresh, whole foods and well-balanced meals.