Others have taken this study as evidence debunking the idea that counting calories is the key to weight loss. While that wasn't the main thrust of this study, nor the instructions given, participants did reduce their intake by an average of 500-600 calories a day (even if they didn't count them). This study didn't prove the unimportance of calories.
The researchers also asked everyone, not just those in the low-carb group, to avoid "added sugars." Therefore, we can't really say anything new about added sugars and weight loss.
What this study does show is that people who have staked a claim on one diet's superiority over another don't have as strong a case as they think. It's hard to overstate how similarly these two diets performed, even at an individual level.
It shows us that the many people, and the many studies, suggesting that we can tell which diets are best for you based on genetics or based on insulin levels might not be right either. Almost all of the studies that backed up such ideas were smaller, of shorter duration or less robust in design than this one. Granted, it's still possible that there might be some gene discovered in the future that makes a difference, but those who think they've found it already might want to check their enthusiasm.
https://www.nytimes.com/2018/03/26/upshot/what-we-know-and-dont-know-about-how-to-lose-weight.html
