Another way to say this: Eat foods with low glycemic index. Avoid foods that spike blood-sugar levels.
Honey, for instance, has a high glycemic index. Watermelon has a high glycemic index. They will not get you fat the same way cane sugar and watermelon juice will.
A juice made of celery, kale, and spinach, will still have a low glycemic index. But it's still nowhere near as good for you as unprocessed celery, kale, and spinach.
Aside from not being evidenced, this is irrelevant to your hypothesis. Watermelon contains little fiber even on a per-calorie basis (https://tools.myfooddata.com/nutrition-facts/167765/wt1) and honey (https://www.nutritionvalue.org/Honey_nutritional_value.html) contains almost none.
How is possible for people to crave steak and eat lots of steak despite having no sugar if the theory is that sugar causes a huge reaction and people to crave more sugar after eating it?
Blaming sugar ignores that all food triggers a spike of dopamine and insulin reaction, unless it's diluted in a lot of water. This is why vegetables are safe for diabetics, due to being so diluted. Jason Fung, Taubes and other fitness/health influencers keep spreading this carbs-insulin nonsense.