The study you linked can't be described as rigorous. They only have 2 groups, without a control group. And they only give them the advice to eat between 12pm till 8pm, and the other group to eat 3 meals a day.
They found there was significant decrease in weight for intermittent fasting group.
The reason they give that intermittent fasting has no effect is because the other group also lost weight, although less.
But since both groups got instructions the study is lacking a control group.
Therefor we shouldn't compare both groups. What is left is to look at intermittent fasting by itself. And there they found what they call significant decrease in weight.
Studying human diet is notoriously difficult. Randomizing people who want to lose weight to 'keep doing everything how you have been' is not going to be a study that anyone enrolls in, so I think this study's methodology was thoughtful and realistic.
The only genuine methodological critique I'm aware of for this study is its sample size.
They found there was significant decrease in weight for intermittent fasting group.
The reason they give that intermittent fasting has no effect is because the other group also lost weight, although less.
But since both groups got instructions the study is lacking a control group.
Therefor we shouldn't compare both groups. What is left is to look at intermittent fasting by itself. And there they found what they call significant decrease in weight.