The only way you'll know for sure is to get blood work done before you make one change in variables. I.E., you take out sugar and keep all else the same. Then check your blood work again. But I promise you one thing. 10 years from now (probably sooner) the Dr.oz types of the world and the majority of the diet community will have completely changed their tune regarding their collective stance on fats.
As far as performance on a "no sugar" diet......you'll be fine. Yams, sweet potatoes, squash, hell even nuts have carbs in them. Now if you cut out the nuts, yams etc now you're talking about what I've been doing for the past few months. The weight loss is tremendous on a "no/very low" carb diet but my performance leaves something to be desired. Like Eagle said above, once I get down to where I want to be I will cycle back in some more carbs and cut down a tad on the fats. If you do decide to essentially cut out carbs, make sure you increase your fat intake and prepare to lose weight. Hope this helps.
As far as performance on a "no sugar" diet......you'll be fine. Yams, sweet potatoes, squash, hell even nuts have carbs in them. Now if you cut out the nuts, yams etc now you're talking about what I've been doing for the past few months. The weight loss is tremendous on a "no/very low" carb diet but my performance leaves something to be desired. Like Eagle said above, once I get down to where I want to be I will cycle back in some more carbs and cut down a tad on the fats. If you do decide to essentially cut out carbs, make sure you increase your fat intake and prepare to lose weight. Hope this helps.