Whole fruits have a ton of dietary fiber. The fiber stays in the system helping you stay full and also aid in defecation. Whole fruits also have tons of vitamins and nutrients.
Fats are also very energy dense. Swapping out 1 tablespoon of maple syrup for 1 tablespoon of butter will yield a similar quantity of calories and each will have different flavors and textures.
I know you keto people love to blame every single ill in the world on carbs and sugars as a whole, however, weight as a whole is simply due to calories. You can argue what each nutrient does to your body, but I chose to just count calories and change my eating habits (including going vegetarian).
I managed to lose 65 lbs over the past 2 years and do plenty of cardio. I guess my weight loss story trumps yours, right?
However, if you STILL don't believe me, consider books by these two professionals:
One's a body builder that explains how he toned his body into competition form, the other is a doctor that describes effective dieting methods.