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Leptin & Cold & Leida & Sukura_Girl

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  • Leptin & Cold & Leida & Sukura_Girl

    I have been thinking about this all morning...

    Leida and Sakura_Girl both said on another thread that they get hungry while they are cold.

    Studies show this shouldn't happen, and many people back this up by saying they are not hungry when they are cold.

    Now, there is a substance called Leptin which circulates in your body. Almost every cell in your body has leptin receptors. When you have just eaten, your brain releases lots of leptin into your bloodstream, this circulating lepting binds with your trillions of leptin receptors and your brain shuts off the hunger signals. When the hunger signals shut down, your brain produces less and less leptin until it is very low--then you are hungry again.

    Things can (and do) go wrong with this system. Some people don't produce leptin--these people are always obese and must get leptin injections. When they get the leptin, they become not obese.

    Some people have leptin resistance (LR). They have lots of circulating leptin, but their receptors are 'clogged' and the brain never gets the signal they should be full, so keeps producing leptin. This is similar to insulin resistance which causes diabetes. Leptin resistance is a very common problem.

    The studies show that when a normal metabolism person is exposed to cold air, ie. 50 degrees F for about 20 minutes, leptin signalling is shut off. Hunger stops when cold exposed, in other words. If someone was LR, that wouldn't happen. The leptin receptors, in their compromised state, wouldn't shut off the hunger signals.

    So what I am thinking, is that a good test for Leptin Resistance would be if you are hungry while you are cold. I'm talking about really cold, not just a cold day. Anyone could try this test easily. Skip your normal first meal of the day and walk outside minimally clothed on a really cold day, or take a really cold bath and see if your hunger abates. I have tested this on myself and it works. If it doesn't that could be an indication of leptin resistance and could help you sort out your diet woes.

  • #2
    no brainer. you will eventually get hungry when you're cold. people live in cold climates and still get hungry and eat meals. this is stupid.

    you can be cold, wet and hungry and it sucks.

    cold therapy and brown fat. really cool. not the answer to life and everything else, though.

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    • #3
      I live in a cold climate and have spent a lot of time outside on cold days. I agree, you will still get hungry. Anyone who's been winter camping or done outdoor sports in the winter can likely attest to that. Your body wants more calories because it's working harder to stay warm, so I find that doing a lot of activity outdoors in winter is likely to make me quite hungry. I used to do a lot of wintertime running (down to -20C in just lined tights, t-shirt, and hoodie), and I would be ravenous after.
      “If I didn't define myself for myself, I would be crunched into other people's fantasies for me and eaten alive.” --Audre Lorde

      Owly's Journal

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      • #4
        Originally posted by otzi View Post
        The studies show that when a normal metabolism person is exposed to cold air, ie. 50 degrees F for about 20 minutes, leptin signalling is shut off. Hunger stops when cold exposed, in other words. If someone was LR, that wouldn't happen. The leptin receptors, in their compromised state, wouldn't shut off the hunger signals.
        Do you have links to the studies?

        I'm not sure if I get hungry when cold, or if I get hungry when I come in and I've been cold, can't remember any specific incidents.
        I would imagine any response would be fairly short lived, otherwise you would never be hungry if you were cold all the time, or cold for a few hours, more like a sudden drop in temp would shut off hunger for a few hours at most.
        I may try getting a cold plunge at the end of a day not eating, see if it turns the hunger off for a bit?
        You know all those pictures of Adam and Eve where they have belly button? Think about it..................... take as long as you need........................

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        • #5
          Originally posted by Owly View Post
          I would be ravenous after.
          I'm not talking after. I'm talking while. I also live in a cold place, Alaska, we all eat all winter and in fact most gain weight. But when a person is exposed to cold, their hunger signals are turned off. This is a well-studied fact in men and mice. It is a function of gene expression at the leptin receptor level as shown here:

          Leptin receptor gene expression has been measured in arcuate and ventromedial hypothalamic nuclei. Receptor mRNA in both hypothalamic areas was higher in obese mice than in lean littermates. Twice daily leptin administration for 7 days profoundly affected food intake, reduced leptin receptor mRNA in the arcuate nucleus, and had a similar effect on neuropeptide Y gene expression. A single leptin injection was ineffective. Exposure of lean mice to cold for 24 h caused an induction of leptin receptor and NPY mRNA which was normalized when animals were returned to the warm. Regulation of receptor gene expression may be an important component in the reading of the leptin signal.

          Everything we do or feel is pretty much just a chemical reaction on some level.

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          • #6
            Originally posted by Tribal Rob View Post
            Do you have links to the studies?

            I'm not sure if I get hungry when cold, or if I get hungry when I come in and I've been cold, can't remember any specific incidents.
            I would imagine any response would be fairly short lived, otherwise you would never be hungry if you were cold all the time, or cold for a few hours, more like a sudden drop in temp would shut off hunger for a few hours at most.
            I may try getting a cold plunge at the end of a day not eating, see if it turns the hunger off for a bit?
            Glad you asked. Yes, lots of them. I kind of stopped putting in links and quotes from studies because most people just gloss over or don't read them. Here are a few:

            Autonomic responsiveness to acute cold exposure in obese and non-obese young women. - Abstract - UK PubMed Central (abstract only -- human)

            Changes in environmental temperature influence leptin responsiveness in low- and high-fat-fed mice (full text -- mice)

            Leptin-specific patterns of gene expression in white adipose tissue (full text -- mice)

            JCI - Beneficial effects of leptin on obesity, T cell hyporesponsiveness, and neuroendocrine/metabolic dysfunction of human congenital leptin deficiency (full text -- mice)

            Low ambient temperature lowers cholecystokinin and leptin plasma concentrations in adult men - ISPUB (full text -- human)
            Last edited by otzi; 06-06-2012, 02:45 PM.

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            • #7
              Originally posted by jakey View Post
              no brainer. you will eventually get hungry when you're cold. people live in cold climates and still get hungry and eat meals. this is stupid.

              you can be cold, wet and hungry and it sucks.

              cold therapy and brown fat. really cool. not the answer to life and everything else, though.
              C'mon man, I don't do this to you. What, you just wait for me to post something so you can troll me?

              Comment


              • #8
                If I read your first study's discussion section correctly, it actually says the opposite:

                The thermostatic theory of appetite is based on the observation that high ambient temperature inhibits appetite and motor activities in animals. Exposition to low temperature elicits hyperphagia and considerably increases motor activity of the organism [8].
                The results of the present study demonstrated a statistically significant decrease in the plasma concentration of CCK (p<0.0005) after a short exposition to low temperature. It has been concluded on the basis of this observation that CCK participates in the short-term regulation of energy balance following exposition to low temperature by potentiating the feeling of hunger and thus increasing the amount of the ingested food. It has been known that a fall in the concentration of CCK elicits hunger and causes an increase in feeding activity [2]. The mechanism of this phenomenon may be both peripheral and central. There could be down regulation of central CCK-B receptors as well as peripheral CCK-A receptors that in term activate vagus nerve [10].
                So it says that the cold created a drop in CCK, and a fall in the concentration of CCK causes hunger. This would seem to support eating more when cold, rather than the opposite.
                “If I didn't define myself for myself, I would be crunched into other people's fantasies for me and eaten alive.” --Audre Lorde

                Owly's Journal

                Comment


                • #9
                  Originally posted by Owly View Post
                  If I read your first study's discussion section correctly, it actually says the opposite:

                  So it says that the cold created a drop in CCK, and a fall in the concentration of CCK causes hunger. This would seem to support eating more when cold, rather than the opposite.
                  Yes, that is true. Exposure to colder temps will cause us to eat more. That is because we need more calories to support the increased metabolism to keep warm, but in the case of exposure to a very cold temperature our hunger shuts off. I'm thinking this is an evolutionary design to keep animals somewhat dormant during really cold weather. Good catch!

                  An example would be, you are outside on a freezing cold day wearing just shorts. You are shivering your butt off. The last thing on your mind should be, 'Gee, I'd like a grass-fed steak'. But when you go inside and get warmed up, watch out ribeye!

                  As a hunter, I see that cold-snaps put animals off of feeding for a few days. I also see it at my birdfeeders.
                  Last edited by otzi; 06-06-2012, 03:06 PM.

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                  • #10
                    Originally posted by otzi View Post
                    C'mon man, I don't do this to you. What, you just wait for me to post something so you can troll me?
                    you post the same shit in 10 threads! coldness is next to godliness.

                    don't worry, i'm never commenting on another cold thread again. that's a promise.

                    Comment


                    • #11
                      Originally posted by otzi View Post
                      Yes, that is true. Exposure to colder temps will cause us to eat more. That is because we need more calories to support the increased metabolism to keep warm, but in the case of exposure to a very cold temperature our hunger shuts off. I'm thinking this is an evolutionary design to keep animals somewhat dormant during really cold weather. Good catch!

                      An example would be, you are outside on a freezing cold day wearing just shorts. You are shivering your butt off. The last thing on your mind should be, 'Gee, I'd like a grass-fed steak'. But when you go inside and get warmed up, watch out ribeye!

                      As a hunter, I see that cold-snaps put animals off of feeding for a few days. I also see it at my birdfeeders.
                      Except that I don't see that in the studies you present, only evidence for the opposite (cold lowers leptin levels, and low leptin drives hunger). The study that shows the drop in leptin and CCK levels in the cold does not state in its design that they waited to test the cold-exposure levels after people warmed up again--since they were looking at the effects of cold on leptin levels, then they would test while the subjects were still affected by the cold exposure, and those levels would have dropped during the 30 minute exposure period and would not be an effect of the body warming post-exposure.

                      Of course if you are outside in the freezing cold wearing just shorts, the first thing on your mind is getting somewhere warm because you are at immediate risk of hypothermia. Being out in temperatures that are survivable but are uncomfortably cold is not the same situation, and in those circumstances, I have experienced being hungry.

                      My assumption on the bird feeder would be that the birds are seeking shelter and are thus not at your feeder, not that the birds aren't hungry. The instinct to find shelter in the cold does not preclude also being hungry.
                      “If I didn't define myself for myself, I would be crunched into other people's fantasies for me and eaten alive.” --Audre Lorde

                      Owly's Journal

                      Comment


                      • #12
                        There's a difference between winter or living in a cold climate or going outside and saying man, it's cold and actually becoming cold as in putting yourself at risk to die and having people yell at you to get naked and get into a sleeping bag and shoving hot drinks in your face while you shiver out of control for an hour. I've been in the latter state. You lose your appetite in this state for sure. And I suppose if you didn't, perhaps there is something wrong with your Leptin signalling, but I don't know. Wouldn't you lose your appetite when you are close to death even if the thing bringing you close to death was something else, like perhaps severe dehydration or maybe as you are falling from a cliff? You're certainly not going to be having much appetite while falling off a cliff.
                        Female, 5'3", 50, Max squat: 202.5lbs. Max deadlift: 225 x 3.

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                        • #13
                          Originally posted by sbhikes View Post
                          There's a difference between winter or living in a cold climate or going outside and saying man, it's cold and actually becoming cold as in putting yourself at risk to die and having people yell at you to get naked and get into a sleeping bag and shoving hot drinks in your face while you shiver out of control for an hour. I've been in the latter state. You lose your appetite in this state for sure. And I suppose if you didn't, perhaps there is something wrong with your Leptin signalling, but I don't know. Wouldn't you lose your appetite when you are close to death even if the thing bringing you close to death was something else, like perhaps severe dehydration or maybe as you are falling from a cliff? You're certainly not going to be having much appetite while falling off a cliff.

                          I guess this is too subjective as everybody's comprehension of cold is different. The studies are kind of a waste because they are on mice for the most part, and leptin levels are different from leptin receptor problems.

                          It was just a thought...

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                          • #14
                            Seems to me like, getting hungry(er) should be a signal that it is working, right? We are getting hungry because our body is working overtime, which is what we want, right? Shivering or trying not to is work, right? Energy out? You just have to be prepared for it. It is just like a workout. When I work out, I am always hungrier. I am not hungry or thinking of food during the work out necessarily, but at some point afterwards I am starving. When I figured that out, I thought it was easier for me to quit working out like a mad woman and get a grip on my calories instead.

                            But from what others have experienced, it will pass, and hopefully it will for me also. I am not hungry while cold. But during the daytime that my fasting window opened up, I was pretty hungry. Thought about buttering up my arm and chewing it off. However today, day 4(?) I was still somewhat hungry but I was prepared for it and got a grip on it today. I havent added up my supper yet, but I should be less than yesterday.
                            65lbs gone and counting!!

                            Fat 2 Fit - One Woman's Journey

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