Let's do a thought experiment. 65'ers wife has 2 drink options, both are 300 calories. One of them is her coffee with coconut oil/pastured butter/whole cream/whatever and the other is a large glass of orange/apple juice (~22 oz). While we're calorically neutral, we are very much not neutral in terms of the response her body will produce. The coffee will provide medium chain fats for fueling whatever she's doing and encourage her body to maintain the fat-burning mode that has begun by her overnight fast. The glass of juice is ~65 grams of sugar. It's essentially an oral glucose tolerance test. The overnight fast will be broken and her body will kick into sugar burning/storing mode. There will be a big blood sugar spike, an insulin response and then the resulting blood sugar drop. In 1.5-2 hours she'll be hungry and ready to eat again at which point, the mid-morning snack adds calories we'd rather not have. Without the big hormonal response, though, she may very well not be truly hungry until lunch.
You're throwing stones at this approach, but you've never tried it. Those of us who have completely recognize that there are positives (and negatives) to it. It's a tool. It can be a very effective tool. It's not a tool that every person will work well with, but it's one that I think anyone interested in diets and nutrition should take an open-minded look at.