In general, in the modern world (or at least, in the US) we tend to overeat. We're not just eating to satisfy hunger, we're eating for many reasons. Furthermore, it takes your body some time to react to putting food in your stomach (this is why you eat more if you eat fast than if you take your time).

Basically what I'm saying is, eating fewer calories doesn't necessarily mean you're hungry, because putting food into your mouth isn't just a reaction to being hungry, and because we tend to eat more than is necessary to satisfy hunger anyway.

I'm not contesting the other points you bring up, but hunger is the major challenge in calorie-restricted diets.

As someone who's currently on a calorie-restricted diet, yes, hunger is a big problem.

However, eating fewer calories by cutting out grains is not the same thing as being on a calorie-restricted diet.

Isn't it automatically a calorie-restricted diet if you are eating fewer calories than you normally would?

FWIW I also have cut out grains but my weight is very stable, so it seems fair to assume I now just eat more of other things.

Define "normally would", because people's calorie intake varies from day to day. Also, previously I claimed that people have a tendency to eat more than they should, so scaling back on that isn't calorie restriction, it's just the absence of extra calories.

More generally, it's just a bit pedantic to say that eating fewer calories than you would otherwise should be called a "calorie-restricted diet". The first reason is because the phrase "calorie-restricted diet" implies a significant restriction instead (for example, I'm only 1200 calories per day right now; that's a significant restriction compared to what I would be eating if I wanted to maintain my current weight). The second reason is because "calorie-restricted diet" implies a diet focused around tracking calories. Cutting out grains isn't a diet focused on calorie intake (heck, it's not tracking calories at all), it's just a diet that has the side effect of likely reducing calorie intake.

Switch to a very high fiber diet, like lots of leafy greens. They slow digestion and can help lower your glycemic index. Most grains are simple carbohydrates, which mean you'll have a rapid increase in your blood sugar, this causes an insulin response. High insulin causes your body to convert said sugar to fat. Over time and weight gain your body can become resistant to the insulin, so it stays in your blood stream longer. Ask any diabetic that has taken too much insulin, that insulin hanging around is a bad thing. You will feel extremely hungry, causing an overeating response, which again raises ones blood sugar. Another insulin shot is needed, and if not dosed correctly puts too much insulin the blood stream. You can see who this leads to a very destructive cycle.

Hunger is not perfectly tied to caloric intake- part of the problem with, say, sugary sodas is that they won't fill you up no matter how much you drink.