Hey Michael, the most important to remember with diet is that your metabolism will adjust.
Low-carb diets work for weight loss because low-carb foots are more satiating and typically higher in protein.
Ken also reported on the fact that he retained less water (and so felt and looked thinner) doing a week of low-carb vs. a week of low-fat.
But if you ate only 1000 calories a day for months on end, you would stop losing weight. Then when you return to normal eating, you will gain a bunch of weight immediately, as you have a 1000 calorie/day metabolism.
While you can grind it out over years by consistently cutting more-and-more calories and adding more-and-more exercise (as it sounds like Ken did), the best tip I can give you is to only diet 2 weeks at a time. https://www.t-nation.com/diet-fat-loss/the-matador-intermittent-diet
PS Be sure to get enough protein (1.6g/kg) while dieting or you will lose equal parts muscle and fat, which will indeed make you even fatter in terms of body fat percentage.