Satiety: You keep Using that Word

..and you're full of it, too!

tl;dr:

• Satiety == meeting internal energy balance

• Everything else is a gimmick

• You can’t usefully define satiety in absence of (internal) energy balance

• We have a feedback system to manage energy intake, but it’s broken in more and more of us over time

• Being full is not the same as being satiated

• Lack of appetite for a food is not the same as being satiated

• Cessation of eating/lack of appetite is not satiety

• (Lean) protein is not “satiating,” it’s just not that appetizing

• Fiber is not “satiating,” it’s just bloating

People think they understand Satiety

Satiety is all the rage for some reason. Hey, I get it: I like satiety as much as the next guy. In fact I’d argue I only discovered real satiety about 6 months ago with heavy cream.

Unfortunately, most people seem to have a vastly oversimplified understanding of satiety, that the average obese person can debunk instantly just by remembering last weekend. (Remember, it only takes 1 counterexample to refute a hypothesis.)

For one, many seem to think of satiety as an inherent trait of any given food. That doesn’t make sense. The human metabolism is complicated and everything in it interacts with everything else.

E.g. is a potato satiating? Is chicken breast?

We can’t answer those questions in a vacuum. Are you eating the potato slathered with butter? Boiled or baked? Salted? Is it a side in a steak dinner? Do you do well on carbs? Are you on day 5 of a water fast? Are you in ketosis? Is this potato #1 or #16 in a long line of potatoes you’re eating? How many copies of the amylase gene do you have?

How different is satiety between individuals?

Probably quite a bit. I’m not sure if these are “normal” differences like height or hair color. It could be that “normal satiety” in humans means one thing, but quite a few modern day humans have broken satiety. In fact, I’m pretty sure many of us have broken satiety. I’m just not sure if, absent that breakage, there would still be differences in satiety between us.

I see people claim to be satiated from things that I know give me zero satiety. I’ve also noticed things giving me zero satiety that normally give me lots of satiety. So even within one person, the context can change quite dramatically.

Fullness is not the same as Satiety

We colloquially conflate the two. And, I suspect, in a healthy human eating a healthy species-appropriate diet, they actually work together. As in, that human would be roughly satiated when physically full or before.

But many of us humans are not healthy, and our diets are not very species-appropriate. I know lots of people that never get satiated, even when painfully full. I consider myself one of them.

I can, and have been, full to the point of pain and even vomiting, yet ravenous. There is simply no feeling of satiety whatsoever. The cessation of eating comes from physical pain, not from the food having had any positive effect on my satiety.

Stupid

The obvious one is refined carbs. I discovered in college that I simply could not get any satiety whatsoever from most carbs. The biggest suspects were of course candy, cake, hamburgers, and so on. One day in college, my roommate and I bought over $100 worth of candy and I puked that night. I was not satiated the minute before I puked, I was just in pain. (Incidentally, this roommate was also the one who introduced me to fat satiety: one time he melted an entire brick of butter onto a pizza, and I couldn’t continue eating long before I was physically full. Should’ve figured this out 20 years ago, I guess.)

Another time I went to an all-you-can-eat pizza place.

Pro-tip: do not go to an all-you-can-eat pizza place!

This was a decade ago and I don’t remember how much exactly I ate. But I must’ve eaten 3 or 4 whole pies when I discovered they also had dessert pizza. I remember eating a whole (sweet) pizza pie covered in M&Ms and one with nougat and I think I ate at least some with white chocolate on it.

That night I was in more pain than I’ve probably ever been. My stomach was so bloated that I couldn’t lie on it or on my side. All the fiber was binding water and clogging up and bloating my gut.

It must’ve been upwards of 5,000kcal in just that one meal. But there was no satiety whatsoever.

Not stupid, but still not satiated

As detailed in a post about my previous dietary experiments, I tried to do a potato-only diet last year. I only lasted a little over 2 weeks.

The potatoes were so filling and bloating that I was both in physical discomfort (not quite pain) and starving (didn’t meet internal energy balance) the entire time.

Yes, I couldn’t eat any more due to sheer lack of space. Yet I wasn’t satiated at all.

That’s why I find the idea that “if only food wasn’t so calorie-dense, we wouldn’t be obese” bizarre. If that was really the thing, why not just eat sawdust? Or drink a ton of water?

The human metabolism clearly has a feedback system that reacts to the amount of available energy it has received. Something as silly as bloating up the stomach obviously doesn’t help at all. If this is news to anybody, I suggest you try dieting even once, lol.

I actually got severe starvation symptoms on the potato diet, because I couldn’t stomach (ha!) more than about 600kcal per day: lower body temperature, heightened adrenaline, inability to concentrate, constant thoughts of food (mostly steak).

Potatoes are so nutrient-light that I would’ve had to eat about 6-7lbs PER DAY to get the same amount of energy I do now.

Caloric density isn’t bad. In fact, it’s great. It saves you the physical bloat and pain of eating what is essentially non-food.

The idea that calorie-dense food is unhealthy is essentially
saying a food is healthy to the degree to which it is not food.

This bizarre idea seems to be why people rave about fiber so much. All fiber does is bind water and bloat your guts. Some of it gets fermented and gives you gas, too.

In terms of satiety or fat loss, fiber does nothing.

If I wanted no calories I could just fast. The added insult of bloating my stomach and giving me gas doesn’t add anything of value.

My Protein Shake Brings All The Boys To The Yard (Cause Protein’s Not Actually That Satiating And They’re Still Hungry)

Some people assume axiomatically, or based on some studies, that protein is satiating.

The origin of this seems to be some weird study where they fed people an isocaloric plate of pasta with either salmon (“protein”), nothing (carbs), or olive oil (“fat”). They then found the salmon eaters were the most satiated and thus PROTEIN IS THE MOST SATIATING. (I might slightly misremember this study, it’s been a while that I read it.)

There’s also this thing about how protein is an “inefficient fuel” as if that had anything to do with satiety.

All else being equal, why would I choose an inefficient fuel? I have to eat 7lbs of potato per day just to get to energy balance. No thanks, I’ll take my cream milkshake.

For me personally, protein doesn’t seem satiating at all. One of the most appetite-inducing things ever for me is whey powder. Maybe that’s due to the (stevia) sweetener or the chocolate flavor, but somehow the actual protein in it doesn’t do jack to counter that.

I’ve also overeaten fatty meat like ribeye steak, 80/20 ground beef, and brisket. I’ll get full in the short term, but 15-30 minutes later I want to eat again. If I go back to the same fatty meat the cycle just repeats until I’m painfully bloated from the meat or I throw the leftovers in the trash. Last time I did 3-4lbs of BBQ meat, mostly brisket, but also some pork ribs and pork sausage links.

Again with the pain but no satiety.

Roast chicken isn’t much better. I’m ok for a while but then, quickly, the appetite comes back.

Now those same people might say “Ok, but try that on dry chicken breast, or unflavored whey isolate!”

Oh, so it’s not all protein that’s satiating then, is it? If the first handful of proteins I mention aren’t “what you meant” then maybe we need a more fitting term. All proteins are apparently not created equal.

I wouldn’t be able to eat 4lbs of dry chicken breast, sure. But again we’re confusing cessation of eating or lack of appetite with satiety. I can’t eat 4lbs of dry chicken breast because it’s disgusting.

Chicken breast is a little denser than potatoes in terms of energy, and I’d only have to eat about 4lbs per day. Of course I’d probably get headaches and other problems because it’s way too much protein and not enough fat.

Protein leverage hypothesis

One theory that makes sense to me is the Protein leverage hypothesis. It posits that you will not reach satiety on non-protein foods until protein requirements are met. That makes sense to me, if we allow that protein requirements might be met with very little protein, much less than is commonly assumed. For example I seem to not care for protein after more than about 0.15-0.2g/lb of ideal body weight. 0.3g/lb of ideal body weight already seems like a bit too much, appetite wise. Recommendations are typically quite a bit higher, in the range of e.g. 0.6-1.0g per lb of lean body mass. Admittedly lean body mass would be a bit lower than ideal body mass, but my 30g are only 0.2g/lb of my lean body mass (150lbs by DEXA).

It also means that protein isn’t “satiating” after its requirements are met. It’s just not appetizing. Those are different things.

If you need more convincing, even among bodybuilders, studies seem to consistently show that protein isn’t more satiating than fat or carbs.

I suspect the very idea that protein is satiating comes from dry chicken breast being very unappetizing and people conflating that with satiety.

Let’s take the idea to the absurd conclusion: you know what’s super unappetizing? Nothing. So is eating nothing satiating? Can we just fast our way out of obesity?

While that has worked for some, for most people, the answer is clearly no. I’ve tried it.

Satiety equals Meeting Energy Requirements

The fundamental misunderstanding seems to stem, once again, from CICO, and go something like this:

1. Obesity is caused by overeating calories

2. Earlier cessation of eating will reduce calorie intake

3. Therefore, cessation of eating will prevent/cure obesity

The problem is, of course, that this is wrong. But if you believe in hard CICO that’s the conclusion you must come to.

For the record, here’s my definition of satiety:

Satiety means having reached internal energy balance,
i.e. meeting all energy needs from intake + available body fat.

Yes, satiety means the body is in energy balance, or even has a surplus. Our feedback system is tuned to provide us with the energy we require to run. If we are in an internal deficit, and thus lack the energy to function, this feedback system will reduce energy expenditure (Calories Out) and increase our desire for food (Calories In). If your model of fat loss/obesity doesn’t include this dynamic feedback system, you can’t design an adequate fat loss strategy.

Tricking this feedback system is as futile as taping over the gas gauge in your car, and hoping it’ll drive farther. You’re shooting the messenger instead of addressing the actual problem: why does the body not seem to have access to the body fat that is clearly present?

Any little trick or gadget that allows you to trick this system misses the point. It’s like filling water into your gas tank to push up the gas needle. The needle is not the problem.

I would argue the real problem is: obese people can’t seem to access their body fat reserves to fuel themselves. We carry a ton of energy around with us as body fat, shouldn’t we be satiated and energetic the whole time? The fact that we’re not, and we are in fact often lethargic and feel like we’re starving all the time, should give us a hint.

Something’s rotten in the state of Denmark.

Now I don’t know exactly what’s rotten. The human metabolism is a complex system, and different people have different ideas.

Stephan Guyenet thinks the brain’s at fault and signaling is broken. Other people think that some of the various energy delivery mechanisms in the body per se are broken and that the signals from the brain are, in that sense, correct - the body is, on a chemical level, starving.

Those could even be the same thing. Actual flux or buffer states can be the signal itself. Imagine the mailman coming by and seeing your mailbox already stuffed with the last few weeks’ mail. The physical presence of excess mail might be the signal not to deliver any more, telling him maybe you’ve moved or are on vacation. In that scenario, the presence of substrate IS the signal.

I like the analogy by Jason Fung here. He describes a gasoline tanker truck running out of gas in its own fuel tank. If there isn’t a way for the gasoline in the big trailer tank to reach the smaller tank, which the truck actually runs on, then all those gallons aren’t of much use.

The question is: which part of the system is broken, and how can we fix it?

Surprisingly, the latter seems easier than the former.

We can sometimes fix it, but we don’t know why

This isn’t actually that surprising. Complex systems often elude our understanding for a long time. There are plenty of heuristics that work pretty decently without us understanding the underlying mechanisms at all. These seem to evolve through trial and error, and culture.

As an example, humans used tree bark as antibiotics, certain plants as medicine or hallucinogens, and evolved rules for dealing with food parasites in pork and other meats, long before any of those were really understood or discovered. We used soap before we had chemistry or even alchemy.

That’s better than nothing. But it’s not exactly science and, while it helps a population on average, doesn’t do much for the individual for whom the evolved rules don’t work.

We are in a similar stage with diet and obesity.

Plenty of anecdotes exist of people losing insane amounts of fat very rapidly on certain diets, or with certain interventions. Then you try them, and they don’t work for you. Sometimes they don’t even work for the same person a bit later! (Ask me how I know.)

One problem is that diet is so complicated that we have a hard time even describing or understanding what changes or choices a certain diet entails.

I “did keto” once and lost 100lbs. Then I kept “doing keto” and gained 100lbs back. Presumably, I did keto differently.

There’s a myriad of factors that can be part of a valid “keto” diet that all interact with each other.

• How deep in ketosis?

• Net carb intake

• Gross carb intake

• Sugar vs starch

• Fructose vs glucose vs lactose

• Artificial sweeteners

• Alcohol intake

• Protein intake

• Training exertion

• Fat intake

• Saturated fat vs. mono-unsaturated vs. poly-unsaturated fat

• MCT intake (e.g. coconut/palm fat)

• Stearic vs. palmitic vs. oleic vs. linoleic acid

• Meal frequency

• Feeding window

• Portion size

• Macronutrients consumed mixed vs. separate

• Micronutrient intake

• Variety of foods

• Palatability of foods

• Were foods ever located in a cafeteria?

• Fiber intake

• Solulable vs. insolulable fiber

• Steady-state vs. pulsed patterns of key variables

• Sleep

• Insulin timing

And those are just the ones I’m currently considering.

While I was “doing keto” both losing and gaining back the 100lbs, what configuration of these factors was I running? They were certainly different, as I was living on different continents in different cultures with different lifestyles between the two.

But how were they different? Would these variables I can think of even capture the thing(s) that actually caused the change?

And the worst thing is, even if there is a certain variable, or set of variables, I don’t know which ones are the important ones to truck! If I knew, I would’ve solved the problem, wouldn’t I? It’s hard to look at Vitamin C levels of sailors, if you don’t yet know that lack of Vitamin C causes scurvy.

Cement-truck satiety

The obvious counter-example to “protein is satiating” and “fiber is satiating” and all those tricks and gadgets, for me, is the cement-truck satiety I get from eating heavy cream on ex150. Be it whipped with instant coffee powder, or just sipping it like a milkshake, it hits like the final scene from Final Destination. (Don’t look that up if you’re squeamish.)

I’ve timed myself: within 4 minutes of eating the first spoon of whipped heavy cream I feel a strong sensation of satiety coming on. About 5-6 minutes in, I simply can’t continue, and I’ll often put the bowl in the fridge for the next day.

This doesn’t always happen. It doesn’t happen, for example, when I haven’t consumed a lot of heavy cream in coffee during the day, as my main calories come from heavy cream.

I typically drink about 1,000kcal/day from morning to afternoon as heavy cream in coffee. On days I haven’t had much coffee, even when eating the same lunch, I notice that the same amount of whipped cream in the evening doesn’t lead to satiety.

On ex150, with whipped cream, my body has a very accurate sense of how much energy it’s already taken in, and if it should consume more. And it will shut down further intake via cement-truck satiety within 4-6 minutes.

How does that work if I could easily overeat all-you-can-eat pizza and fatty meat, never reaching lasting satiety?

Interestingly, some readers have tried this, and some have reached cement-truck satiety while others haven’t. So it sometimes works, but sometimes doesn’t. I’ve tried to ask and find out what else they are doing that could be making the difference, but haven’t found anything obvious.

Maybe he rest of ex150 somehow puts one in a context where cream (or any saturated fat, or any fat, or any energy intake) leads to pretty much instant satiety. It is a somewhat severe elimination diet, after all. In which case the solution could be to go full ex150 (or at least eliminate whatever the X factor is).

Maybe some people aren’t wired to reach satiety through (saturated/dairy) fat. In which case the solution could be to find the diet that allows you to reach satiety based on your own genetics.

Maybe some people’s satiety signals are broken in different ways than mine. In which case the solution could be to find the diet that allows you to reach satiety, based not only on your genetics, but whatever other factor broke it in the first place.

Vague Hypothesis of Broken Satiety as the cause of Obesity

Obviously total speculation, but fits my observations while more naive theories like CICO do not.

Observations:

1. We have a built-in feedback system to regulate energy intake

2. This system still works perfectly in maybe 25% of people (thin ones)

3. It works so-so in maybe 25% of people (slightly overweight ones)

4. It works pretty badly in another 25% (overweight/obese) and catastrophically fails in 25% of (very obese) people

5. It used to work much better in the past

6. It has continuously gotten worse over time

7. I cannot seem to reach satiety on (certain) carbs, even eating obscene amounts of energy (5,000kcal+ in one sitting) in some context

8. I cannot seem to reach satiety on fatty meat, even eating obscene amounts of energy (5,000kcal+ in one sitting) in some context

9. I will reach total, lasting satiety within 4-6 minutes (!) of eating 200-300g of heavy cream (context: ex150, ate enough cream prior that day)

10. Some readers report reaching the same hard-hitting satiety from heavy cream

11. Other readers report not reaching it

My conclusion is that we have a feedback system for managing our energy intake that evolved over hundreds of thousands of years, and something in the modern (1850+?) era is breaking it, and increasingly so.

What exactly is the breaking change? I wish I knew.

There are a whole bunch of suspects, of course. It could be something we added in increasing amounts since then (sugar, seed oils, fructose, microplastics, chemical contaminants, stress). It could be lack of something (physical activity, micronutrients, sunlight, good sleep, contact with nature).

We can approach the problem from several angles.

1. Epidemiology: when did this start happening, where, to whom?

2. Mechanistic: what does the biochemistry look like?

3. Black-box experimentation: try random stuff and see what happens.

The crazy thing is, #3 seems to actually work the best. It seems our metabolism is complex and varied enough that the best way to reach any given outcome is to try random stuff until something works. Then we can backfill the mechanisms and see why that outcome happened.

Personally I’m not very bullish on epidemiology. We don’t even know what facts to record a lot of the time. Historically, epidemiology seems to have done more damage than good in nutrition and diet.

At best epidemiology (even the fancy versions like Mandelian randomization) can give us hints, and tell us where to look more closely. But, ultimately, we’re varied and complex enough that what works “for the Japanese” just might not work great for Bob in Ohio.

So crazy experiments it is.