In general, the macronutrient composition of a diet (how many of your calories come from dietary fats, carbohydrates, protein, and Alcohol) serves less of a role in weight loss attempts than does caloric intake overall; increased caloric intake as an independent variable is more than sufficient to explain the current obesity epidemic. There is insufficient evidence to support the role of high fructose corn syrup in inducing obesity
Independent of the macro composition of your diet, a net negative energy balance (consuming less calories than your body needs) is alone responsible for weight loss.
The results of this study showed that it was energy intake, not nutrient composition, that determined weight loss in response to low-energy diets over a short time period. 
Even with extreme changes in the fat-carbohydrate ratio (fat energy varied from 0% to 70% of total intake), there was no detectable evidence of significant variation in energy need as a function of percentage fat intake. 
Neither diet offered a significant advantage when comparing weight loss or other, metabolic parameters over a 12 w period. 
Both the high-carbohydrate and high-protein groups lost weight (-2.2+/-0.9 kg, -2.5+/-1.6 kg, respectively, P Diet composition did not affect the magnitude of weight loss 
Overall, weight loss of 5.2 +/- 1.8 kg was achieved independently of diet composition. 
Weight loss was 7.3 +/- 0.3 kg with both diets 
Overall weight loss was 6.2 (SD 7.3) kg (P 
The magnitude of weight loss and the improvements in insulin resistance and cardiovascular disease risk factors did not differ significantly between the 2 diets 
Weight loss (7.9 +/- 0.5 kg) and total fat loss (6.9 +/- 0.4 kg) did not differ between diet groups. 
... both dietary patterns achieved net weight loss and improvements in cardiovascular risk factors. 
In summary at identical energy intake and similar substrate composition, the dissociated (or 'food combining') diet did not bring any additional loss in weight and body fat. 
All interventions reduced weight (DO 8.9 +/- 1.6%, DA 10.6 +/- 1.7%, and DC 8.7 +/- 1.7%; P 
This study showed that independently of the method for weight loss, the negative energy balance alone is responsible for weight reduction. 
In obese, insulin-resistant persons, a calorie-restricted diet, moderately lower in carbohydrate and higher in unsaturated fat, is as efficacious as the traditional low-fat diet in producing weight loss 
Both trials showed better weight loss on the low-carbohydrate diet after 6 months, but no difference after 12 months. 
weight loss that was completely accounted for by reduced caloric intake
Among persons living in a controlled setting, calories alone account for the increase in fat
Many diets, both fad and more long-term diets, do work. This is mainly because they reduce calories.
When people switch to a paleo-lithic (hunter-gatherer diet), the foods they switch to are naturally more filling (higher protein, fiber, water content) or have less calories for the size of the food eaten (due to water content; a pound of broccoli has less calories than a pound of grains).
When people switch to a ketosis diet (very low carb), the higher fat and protein levels naturally provide satiety and fill people up. Also, there is some evidence that obese people have a maladapted response to serotonin (of which carbohydrates aid in the synthesis of) and thus omitting carbohydrates omits cravings. People lose weight on a ketosis diet because they eat less on a day to day basis, and avoid large binges caused from carbohydrate cravings.
Diets that manipulate fasting (Intermittent Fasting, Alternate Day Fasting) may have some benefits on the 'calories out' side of things as prolonged fasting might increase heat expenditure, but the most significant means for weight loss here is that you control eating. It is much harder to overeat in 8 hours than it is in 16.