Results: The mindset of indulgence produced a dramatically steeper decline in ghrelin after consuming the shake, whereas the mindset of sensibility produced a relatively flat ghrelin response. Participants' satiety was consistent with what they believed they were consuming rather than the actual nutritional value of what they consumed.
What this means is that eating something labeled as healthy causes the body to react as if it has eaten very little, so you sill still feel hungry after eating it and will want to eat more. Combine this with the 'Health Halo' effect and you have a recipe for overeating and obesity. If you think that a food is healthy, you will underestimate the calories it contains, and your body will actually react as if you ate less calories and make you feel like you need to eat more.
This is another reason why it is very important to know the calories in the food you eat. If you underestimate the calories, then your body will actually have the wrong biochemical response to the food, which could lead to nasty things like metabolic syndrome. Because people always underestimate the calories in restaurant food, you should avoid restaurants whenever possible, or only go to places that post the calorie counts.
The good news is that you can take advantage of this. This is speculation on my part, and assumes the effect is symmetric, but it might work. If you baked a low-calorie dessert but told your guests it was grandmother's recipe, with a whole stick of butter melted in, and served them a small portion of this "indulgent treat", they might react as if they had eaten a lot of calories. They should feel full, without actually consuming the calories.
You can also alter the way your own body reacts to food. This kind of conditioning is a bit trickier, but it can have huge payoffs. If you manage to convince yourself that an apple is a high-calorie, indulgent treat, then you can use it as a placebo to cure your feelings of hunger. Each time you bite into an apple, imagine yourself eating a rich apple pie. Close your eyes and imagine the dessert you ate last Thanksgiving. Visualize yourself eating several helpings of apple pie as you eat the apple. If you repeat this process each time you eat an apple, you might be able to trick your body into feeling full. It is worth a try.
If you already have a good way of making the placebo effect work in your favor, like prayer or meditation or exercise, then this is another thing that it can apply to. If you ask God to make you feel less hungry, and you really believe that He can and will do so, then you will feel less hungry and eat less. I am surprised that pastors have not told people this. It is less dramatic than most 'faith healing' and would require a long-term commitment, but it would work.
The broader lesson here is that the human subconscious is very complicated and powerful, and it often works against your better interests. People are programmed to seek out and consume as many calories as they can. This habit was necessary to stay alive for 99.9% of human history, but is a serious problem in modern society. There are a lot of other habits like it. In order to free yourself from those habits, it is necessary to understand and alter the way your mind works. This is hard work, but very rewarding. If you understand the desires and impulses of your primitive mind, you can deal with them and not let them control you.