Skittles or sweet potatoes?
When it comes to fat loss, if calories are equated it really doesn't matter. All carbohydrates are broken down into glucose in the body. One package of Skittles contains the same amount of carbs and calories as approximately 1.5 fair trade raw paleo organic helper-monkey picked sweet potatoes. :-D Carbohydrates are one of the three macronutrients needed by the body for healthy function. They are also the body's preferred source of energy (powering your best workouts!) and they have a close relationship with our metabolic hormones; they help to keep metabolism balanced and healthy.
Skittles and sweet potatoes do have some differences, obviously! They are both broken down into glucose in the body, but the latter will tend to keep us feeling fuller for longer due to fiber content. Fiber slows carb breakdown and absorption. When we feel more full we tend to eat less, which equates to less calories consumed and thus less potential for body fat to be gained. Skittles will not make you gain fat because of the sugar content. They can however make you gain fat because they are easy to overeat; they've been flavor-engineered to be hyperpalatable. A sweet potato will also have more micronutrients, vitamins, and minerals benefiting overall health, which would be missed out on if candy were chosen instead.
Is sugar addictive? Answer me this... do you ever find yourself sneaking down to the baking cupboard in the middle of the night, spoon in hand to dip into the big bag o' granulated sugar? Do you have sugar cubes stashed around the house?
Is sugar causing the obesity epidemic? It is so easy to blame all of the world's health problems on one tangible thing, but in reality disease and obesity are caused from an enormous range of factors. In actuality sugar and overall carbohydrate has been on the decline since 2000 as obesity continues to increase (see graph below by Stephan Guyenet, PhD, author of The Hungry Brain).
Just use moderation. All this finger pointing does is set us up for a bad relationship with food. Black and white thinking, the labeling of good foods and bad foods we *think* puts us in control, but really it gives the food control over us. The moment that we label a food as bad and off limits is the moment that it becomes 'forbidden fruit' and has power over us. Our avoiding means that we're 'good' and when we inevitably slip up and eat it (probably binge), that means that we're 'bad', and feelings of guilt and poor self-worth follow. We are letting a food dictate how we feel about ourselves. Thrive in that grey area and employ moderation. Prioritize protein, eat your veggies, make the majority of your carbs be fibrous grains and starches, and eat some Skittles if you want to.