What really makes you feel full?


The three generally accepted “satiety” hormones are: Cholecystokinin, Ghrelin, and Leptin

Cholecystokinin (CCK) seems simple enough. When the small intestine detects macronutrients CCK is released, binding to CCK receptors throughout the nervous system, mediating digestion and satiety.

Leptin similarly inhibits hunger, but over the long term rather than short term like CCK. It is produced by adipose tissue and seems to counteract a few neurotransmitters that increase hunger. The name of the game is decreasing the activity of the neurons in the Arcuate nucleus of the brain.

Ghrelin stimulates hunger by stimulating the Arcuate nucleus and seems to be primarily responsible for the “reward” feeling from good food, and alcohol. It is released by the stomach and pancreas, but how exactly is this triggered?

Is is possible a micronutrient deficiency causes hunger? What is the biological mechanism for this?


This is quite interesting. I know they have diet pills that are supposed to stop people from feeling hungry. I wonder if it is possible to properly manage this to enable one to choose when they want to feel hungry, and when to not feel hungry. Have we mastered this with the diet pills?

I would have expected to hear of people not eating for several days or weeks with the help of these pills, and likely having terrible nutrition issues if they worked properly.


I’ve found that a tablespoon of MCT oil in my diy mix kills my appetite for several hours. Mixed with the more complete than usual nutrient profile of my new diet, I don’t really get hungry for at least 8-10 hours, but then I was already used to doing some intermittent fasting.

A bit of hunger doesn’t scare me and is easier to ignore if I have a full nutrient load already in my system. The difference between ‘surface’ hunger and ‘real’ hunger. I did read something interesting a while back that suggests the sensation of hunger trips a biochemical mechanism in the brain that helps prevent dementia in the long term.

Satiety and MCTs
Physiological Effects of Medium-Chain Triglycerides: Potential Agents in the Prevention of Obesity1

Brain health and hunger
"Hunger in the Absence of Caloric Restriction Improves Cognition and Attenuates Alzheimer’s Disease Pathology in a Mouse Model"

Doesn’t bode well for the future mental health of the supersized society we live in, does it?


These are both fascinating papers. Thank you for sharing.


What exactly is MCT oil, and where can I find it? Yes it contains Medium-Chain Triglycerides, but is this oil in the nutritional supplements section, or is it one of those hard to find oils such as hempseed oil? I really need something like MCT oil to control hunger so I can follow a sensible diet and exercise plan. Currently, if I try to reduce calorie intake I get much more hungry and end up eating a 1200 calories meal too often, gaining weight and eating the wrong foods. I believe uncontrollable hunger is the reason almost all diets fail.


http://www.amazon.com/dp/B0041TXXLO?tag=19-82341-20 is the MCT oil I have found in DIY soylent recipes. It is not cheap but it seems like a great product!


I’m using the same MCT oil as @nbiller. I haven’t seen it in my local stores, though you should be able to find coconut oil, which is a MCT.


That could explain why, when I do a fried egg sandwich with coconut oil, I feel happy and fed. But if I use ordinary vegetable oil, my system demands “another fried egg sandwich”. Interesting.

I recently heard about coconut oil through a nutritionist on the internet who explained the different mechanism of this oil. The MCT angle is interesting also.



I started taking coconut oil 3x per day back in November. It actually makes me a lot hungrier! Crazy hungry, wake up in the morning before my alarm because I’m so hungry type deal. This effect is several hours after each dose, most noteably in the morning after my evening dose was at about 9pm. At the same time I have lost weight. I have always felt very full after eating very small amounts and it hasn’t changed that at all. Interesting that it can have a different effect on different people.


I think they’re going to find the science of hunger, once proper tools are developed to study it, is totally amazing.

You know the advice that you should have breakfast so that you’re not famished (and hence overeat) during the day? Doesn’t work with me. I have breakfast and the whole day my system is in “Feed Me!” mode.

So I totally believe that we’d have opposite reactions to the same thing.



Actually, I’ve never heard that. I’ve always heard that eating breakfast jumpstarts your metabolism. So it should make you feel hungrier throughout the day, but the point is supposed to be that your body will also use more of the calories you eat.


I’d rather skip breakfast if I can. When I eat breakfast, I usually eat a much bigger lunch and bigger dinner. I believe the increase in metabolism is not enough to make up for the extra calories eaten. If you want to increase your metabolism, then some exercise in the morning would be helpful, much better than sitting around eating another meal. I think this “breakfast is the most important meal of the day” thing is just a sales pitch pushed by people making money off of selling more food and more diets and more expensive health care.


I saw the ref to Leptin on one of the intro pages and found it here via your search function. Been looking for further info on Leptin since about 1995, when a big university (forget who) announced it’s discovery as something lacking in patented lab rats that had been bred to be obese.

By synthesizing what was lacking and (calling it Leptin) then giving some to the obese rats, the rats got skinny, and more physically active.

About 10 years later (2005) another university (OHSU - local to me) put out a nearly identical press release. The magic ingredient was also called Leptin. In media coverage it looked like original research, not confirming research, but that could have been a transcription FAIL by the non-science media.

All subsequent references to Leptin (HFCS may or may not supress it) have been oblique and not product oriented.

I presume that there is no generally recognized as safe supply of Leptin as a nutritional supplement, thus it is not a specific ingredient in Soylent™. Correct?


An internet search about Leptin will probably show Leptin is a hormone - that can’t be simply put in a pill or food. It may have to be injected and maybe isn’t stable enough to store after it’s produced in the lab. Some people have been known to become resistant to one of the satiety (anti-hunger) hormones similar to insulin resistance, such as when a person who over eats and is obese has a blood chemistry that shows their body is always screaming for them to not eat.

I sure would like to see more research into what makes people hungry and what causes satiety or lack of hunger. Too often the current treatment only treat the symptoms or the damage done to the body after years of overeating. I think a lot of foods are addictive, and what is addictive for one person may not be addictive for another. Lack of research exist on how to block such addictions. In high school I hoped there would be something to get rid of hunger without having to eat pounds of food, but decades later there still is nothing that seems to work. I think ready-to-eat foods would help me, because if I’m hungry when waiting for something to cook, I end up eating a lot more by time the food is ready, much more than if I could have been able to grab something and eat and then go on to something else other than food.


Thanks nbiller and kennufs for the helpful information about MCT oils. I’ve tried palm oil and mixing palm oil with other oils. Also I tried experiments with flaxseed oil in attempting to balance omega 3 and omega 6 oils. I’ve failed to stop hunger, but I find some oils such as corn oil or plain vegetable oil seems to be addictive compared to palm oil or flaxseed oil or olive oil. This is probably the type of thing that works for some people and not others.


Breakfast works if breakfast is the cause. If people feel famished for other reasons…breakfast might not necessarily stop it.