Downing sugar and refined carbs like white bread and bagels won't help you lose weight, but it's not only because those foods tend to be high in calories — it also has to do with insulin. Jason Fung, MD, a nephrologist (kidney specialist), explained that processed carbs and sugary foods such as ice cream, cookies, crackers, and regular pasta spike your insulin levels. Keeping your insulin levels low will help you reduce your overall body fat percentage.
Aside from being high in carbs and calories, these foods are low in nutrients (unlike their whole-grain counterparts), so you end up feeling hungry, which makes you eat more. Eating sugary foods also increases your cravings for them, which is another contributor to overeating.
It's OK to enjoy sugary treats and processed carbs every once in a while, but if you cut down on these types of food, you'll definitely notice a difference in how you feel and how your body looks.