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Why do ketogenic diets affect some people's appetite?

magnusthenerd
magnusthenerd Posts: 1,207 Member
Clearly not everyone one's, but I find it interesting to consider why some people's hunger is impacted by ketogenic diets.
I've heard insulin control as one explanation. I find this explanation unsatisfactory because if excess insulin played a large part in excess appetite, losing weight would be a virtuous cycle, even becoming a vicious cycle as one went into underweight. As one lost weight, one's insulin would go down, thus appetite, thus weight, thus insulin. ad nauseum.

I've heard possibly explanations along the lines of a type of hyper-alert arousal state because of the part of ketogenesis that mimics starvation. It would seem if anything, this would make one more alert to food cues.

I've heard paleo-like claims that ketosis is a human's natural state and therefore balanced. I find a lack of evidence of any traditional human diets ever being regularly ketotic.

Personally, I think the ketosis appetite affect is highly psychological. To put it simply, putting a number of foods as firmly off the menu - so to speak - is actually a relief to willpower. Mental fatigue doesn't come simply from sticking with a decision - it may be more expensive to actually make a decision. These autopilot decisions on carbs may free up mental resources to deliberate on quantities of the foods that are still available.
It may also be that by eliminating one of the components of hyper-palatable foods, one eliminates many of them that are probably part of the modern diet issue.

Replies

  • lemurcat2
    lemurcat2 Posts: 7,899 Member
    edited January 2019
    One possibility is that people who find keto helpful had a reaction to quick carbs so that they had a spike of energy and then crash, which seems like a need for more food. Many say they felt like they needed to eat all the time with carbs and not having that is a big (and helpful) change.

    I have never felt like I couldn't go hours without food (if for some reason I wanted to) -- for much of my life I wouldn't eat anything 'til mid afternoon, and find it normal and easy not to snack between meals, even when I go from noon to 9 or 10 before dinner, so the claim that eating carbs means you have to eat all the time puzzled me, but it certainly could be something some experience.

    It reminds me of how lack of sleep can affect me. I am low on energy and often perceive that as "I need to eat," although in that case if I just have coffee I wake up. If I instead eat a quick carb (or carb+fat) to wake up, I will usually find myself wanting to eat all day.

    All that aside, I also think that for some it is psychological in that they've cut out a lot of foods they love and often haven't yet found foods that are as appealing to them, especially if they end up eating a very limited diet. (Remember also that a lot of people who say this are new to the diet -- I know old-timers say it too, but it seems more extreme with newbies. There is a subset of newbies on ALL diets that all of a sudden find they are satisfied on very little food or even claim they couldn't possibly eat more. I think that's a combination of the same forces or often just a realization that they DON'T need to eat all the time -- many people who have been overeating were responding to mental hunger (food is here, looks yummy) vs. hunger due to need for food, and finding ways to address that (I am not a person who eats that anymore, and won't even consider it) can make it easier).

    Re the "available food just isn't that interesting" -- I've had that happen when I have a dinner that didn't turn out that well, but isn't horrible, just not very good. I'll eat it for a while and then feel super full and stop eating even though I didn't eat all that much. In that case I'm likely to be hungrier the next day, but then I have more choice the next day. Anyway, I definitely think this is part of why monodiets work (potatoes, carnivore, hard boiled eggs, etc.) -- food becomes quite a bit more boring.
  • Fatty_Nuff
    Fatty_Nuff Posts: 273 Member
    edited January 2019
    Personally, I think the ketosis appetite affect is highly psychological. To put it simply, putting a number of foods as firmly off the menu - so to speak - is actually a relief to willpower. Mental fatigue doesn't come simply from sticking with a decision - it may be more expensive to actually make a decision. These autopilot decisions on carbs may free up mental resources to deliberate on quantities of the foods that are still available.
    It may also be that by eliminating one of the components of hyper-palatable foods, one eliminates many of them that are probably part of the modern diet issue.
    I totally agree with this! Some people swear the loss of appetite on these diets come from ketones, and a reduction of sugar in their diet and thus no "insulin spikes". Whatever that means. I come from the generation where our mom's told us we couldn't have a cookie because it would spoil our appetite! Just my opinion, but like you, I believe any hunger set off by consuming a sugary food is psychological. Insulin and sugar are not boogeymen.
  • moe0303
    moe0303 Posts: 934 Member
    This is a good question. I do think that there a distinction which could be made between "hunger" and an "urge to eat". In my own personal experience, I found that while I was on the LCHF diet, in addition to be satiated, I no longer had the constant urge to eat that I have experienced most of my life and again experienced after going off the diet. The only other time when I didn't have the constant urge to eat was when I was prescribed phentermine (which faded after 4-6 months).

    and before....I make to claim as to the cause of either period when my urge to eat was diminished. I'll be watching this thread to see people's theory though.
  • moe0303
    moe0303 Posts: 934 Member
    This is a good question. I do think that there is a distinction which could be made between "hunger" and an "urge to eat". In my own personal experience, I found that while I was on the LCHF diet, in addition to be satiated, I no longer had the constant urge to eat that I have experienced most of my life and again experienced after going off the diet. The only other time when I didn't have the constant urge to eat was when I was prescribed phentermine (which faded after 3-5 months).

    and before....I make no claim as to the cause of either period when my urge to eat was diminished. I'll be watching this thread to see people's theories though.
  • moe0303
    moe0303 Posts: 934 Member
    This study might be pertinent to the discussion. It's findings may suggest that ketosis alters hormones which affect appetite.
  • JeromeBarry1
    JeromeBarry1 Posts: 10,182 Member
    This is my 11th day on a low carb high fat intake. I've had no feeling of hunger. That simply indicates that I've expressed no ghrelin. When I eat fatty meals, I'm satisfied. That means I do express leptin. When I test, I find ketones.

    In the sense of discussing "sugar addiction", I don't honestly believe that I have been strongly addicted to sugar. I was able to lose weight and stay within a calorie budget for a big majority of days prior to keto. The decision to start doing keto was for reasons unrelated to any weight loss expectation, although I've lost now 11 lb of mass, most of which was water.
  • leanjogreen18
    leanjogreen18 Posts: 2,492 Member
    nvmomketo wrote: »
    Sone find carbs trigger cravings which feels like a hunger. Carbs do this for me. The fewer carbs I eat, the less drive I have to eat. Part of that is hyperpallatable foods. They affect me badly, but other carbs, over about 10g at a sitting affects me too. My n=1.

    True story, yesterday I had planned to have a single piece of candy after my exercise. I exercised and had the piece of candy. I experienced a dopamine rush, felt wonderful, and wanted to eat more. I fixed my high fat breakfast and ate it right away. Maybe that was ghrelin. If so I leptinated it.

    I didn't think hormones responded this quickly that's why a diet break of at least 2 weeks is recommended?
  • magnusthenerd
    magnusthenerd Posts: 1,207 Member
    moe0303 wrote: »
    This study might be pertinent to the discussion. It's findings may suggest that ketosis alters hormones which affect appetite.

    Interesting. It seems the primary hormonal difference was ghrelin - subjects that achieved ketosis had ghrelin suppressed in comparison to those that did not enter ketosis. The ghrelin also went back up while eating more on the refeed part, which one would expect it not to as volume of food should have increased.
  • lemurcat2
    lemurcat2 Posts: 7,899 Member
    I think often if you cut something out and generally consider it off limits, you can get a desire to eat and eat and eat and just generally overreact to having it again. It might be for all kinds of physical reasons, or it might just be mental in that way.

    As I said above, for many people -- including me -- when you first start something and have a plan and program and are channeling food thoughts into excitement about eating a certain way or a weight loss plan, you can simply not be hungry. I don't think that's limited to keto.

    If I am really focused on nutrition or training, and eating in a generally mindful and healthy way according to my overarching plan, I'm not hungry. If I go off plan for a few days and start to snack a lot of anything tasty that's around and have more high cal meals and so on, I can easily fall back into wanting to eat all the time (even if my macros don't change and I eat lots of foods that are normally really satiating for me too). That's what makes maintenance harder for me than losing, and why I like to do diet experiments or train for things.
  • moe0303
    moe0303 Posts: 934 Member
    moe0303 wrote: »
    This study might be pertinent to the discussion. It's findings may suggest that ketosis alters hormones which affect appetite.

    Interesting. It seems the primary hormonal difference was ghrelin - subjects that achieved ketosis had ghrelin suppressed in comparison to those that did not enter ketosis. The ghrelin also went back up while eating more on the refeed part, which one would expect it not to as volume of food should have increased.

    It also mentions increased leptins. Which may have contributed to the suppressed ghrelin, or it could be a separate thing altogether.
  • magnusthenerd
    magnusthenerd Posts: 1,207 Member
    moe0303 wrote: »
    moe0303 wrote: »
    This study might be pertinent to the discussion. It's findings may suggest that ketosis alters hormones which affect appetite.

    Interesting. It seems the primary hormonal difference was ghrelin - subjects that achieved ketosis had ghrelin suppressed in comparison to those that did not enter ketosis. The ghrelin also went back up while eating more on the refeed part, which one would expect it not to as volume of food should have increased.

    It also mentions increased leptins. Which may have contributed to the suppressed ghrelin, or it could be a separate thing altogether.

    Yeah, Leptin rises with any weight loss. Ghrelin suppresses appetite, Leptin raises it.
    It looked like the findings were that ketosis had no impact on Leptin. When the people - whether in or not in ketosis - did a refeed, their leptin dropped, which is expected on refeeds that last for a week or more.
  • mmapags
    mmapags Posts: 8,937 Member
    moe0303 wrote: »
    This study might be pertinent to the discussion. It's findings may suggest that ketosis alters hormones which affect appetite.

    Something along these lines is what I suspect. I just don't find fat that satisfying. So, I have trouble understanding how it can be that. Fat does affect hormones though...