I had a feeling you would post Jason Fung on this thread eventually. I'm familiar with him, some would say a former fan of his back when I too would strawman against the reality of calories in versus calories out. I wouldn't go as far as to call him a charlatan, but he does have an incentive for people to gobble up this insulin model of obesity (books to sell)!
There are numerous studies comparing keto and non-keto diets, under tightly controlled settings that show no difference in actual fat loss. Remember, higher fat oxidation rates are expected when your diet is largely comprised of fats.
Low carbohydrate versus isoenergetic balanced diets for reducing weight and cardiovascular risk: a systematic review and meta-analysis.
Trials show weight loss in the short-term irrespective of whether the diet is low CHO or balanced. There is probably little or no difference in weight loss and changes in cardiovascular risk factors up to two years of follow-up when overweight and obese adults, with or without type 2 diabetes, are randomised to low CHO diets and isoenergetic balanced weight loss diets.
https://www.ncbi.nlm.nih.gov/pubmed/25007189Ketogenic low-carbohydrate diets have no metabolic advantage over nonketogenic low-carbohydrate diets.
KLC (ketogenic, low-carbohydrate) and NLC diets were equally effective in reducing body weight and insulin resistance, but the KLC diet was associated with several adverse metabolic and emotional effects. The use of ketogenic diets for weight loss is not warranted.
https://www.ncbi.nlm.nih.gov/pubmed/16685046Energy expenditure and body composition changes after an isocaloric ketogenic diet in overweight and obese men.
The isocaloric KD was not accompanied by increased body fat loss but was associated with relatively small increases in EE that were near the limits of detection with the use of state-of-the-art technology. This trial was registered at clinicaltrials.gov as NCT01967563.
https://www.ncbi.nlm.nih.gov/pubmed/27385608However, the best study would be the below:
No Significant Effect of Dietary Carbohydrate versus Fat on the Reduction in Total Energy Expenditure During Maintenance of Lost Weight: A Secondary Analysis
In other words, when conducting the analysis originally planned by the authors we found that the significant increases in TEE with the low carbohydrate diet that were reported by Ebbeling et al. disappeared. Furthermore, the TEE effect modification by baseline insulin secretion also disappeared.
https://www.biorxiv.org/content/10.1101/476655v1This was a follow-up study to the Effects of a low carbohydrate diet on energy expenditure during weight loss maintenance: randomized trial which you can read here:
https://www.bmj.com/content/363/bmj.k4583Scientific literature aside, I would urge you to experiment yourself with both carb and no/low-carb diets and see how you fare. But remember, for your conclusion to have any meaning; net caloric intake must be controlled!
You will never find a study showing a preference for ketosis from a metabolic perspective,
as long as the caloric deficit is equated. The thing is people (self included) will cut carbs and suddenly be consuming far less food, creating an even greater deficit. The foolish among us conclude "ha, I cut carbs and didn't worry about calories, therefore it's all a matter of insulin and calories don't matter!"
I even took this a step further, doing keto but with caloric intake above my maintenance. Despite being keto, I still gained weight - insulin secretion is not reliant on only carbs!