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> So while you may feel that coffee is giving you more energy, it’s simply telling your body that your energy reserves are good to go even after they’re long go
by foobarbazqux 13y ago
> So while you may feel that coffee is giving you more energy, it’s simply telling your body that your energy reserves are good to go even after they’re long gone.
I'm not an expert by any means, but this isn't quite what I learned in my undergraduate course on metabolic biochemistry. Caffeine simply encourages you to burn more energy by the mechanisms outlined by the author. However, you cannot burn energy reserves after they are gone. Where would the energy come from? You have carbohydrate reserves and you have fat reserves. Carbohydrates will go first, and once depleted caffeine will cause you to burn more fat than you normally would. The effect is somewhere around 10% for average consumption levels. When you have burned all of the usable carbohydrates and fat in your body, you start burning protein. That is called ketogenesis. It results in muscle breakdown, and the ketones produced are one of the reasons crack addicts smell kind of funny. Caffeine will not induce ketogenesis unless you are drinking way too much and not eating nearly enough. Note that there aren't super sharp transitions from carbs to fat and from fat to protein.
- legitsource 13y agoKetosis is an alternative method of using fats for energy in the absence of normal process using glucose. The presence of ketones on your breath makes a "fruity" smell that can range from minor to fairly unpleasant. It may make your mouth taste "metallic". When your body is breaking down protein for energy, you will smell like ammonia, which is significantly different smelling than ketones like acetone.
- deleted 13y ago[deleted]
- foobarbazqux 13y agoOkay, so ketosis (ketogenesis?) is one step before breaking down proteins, i.e. first you smell like ketones, then you smell like ammonia?
- legitsource 13y agoBasically, you don't have to enter ketosis on the way to burning proteins for energy. If you stop eating entirely, you will enter ketosis and also be breaking down some protein for energy as soon as your blood glucose and your liver glycogen is depleted (your brain still needs about 20 grams of glucose a day even in ketosis, so gluconeogenesis will occur turning protein into glucose). You probably won't even smell the ammonia at this rate, since it's pretty low. After being in ketosis for a while (a few weeks) your body gets better at producing ketones on demand instead of just supplying them all the time and the acetone smell decreases substantially, but you still shouldn't be breaking down protein unless you are low body fat and not eating enough fat for the calories you need. I never smell like ammonia unless I'm working out really hard and in ketosis. If you aren't lazy, you can work hard enough to smell like ammonia no matter what you eat if you are pushing yourself really hard in an anaerobic exercise set.
- foobarbazqux 13y agoWow, that was an awesome explanation. Thanks.
- legitsource 13y agoNot a problem at all.
- deleted 13y ago[deleted]
- jdminhbg 13y ago> When you have burned all of the usable carbohydrates and fat in your body, you start burning protein. That is called ketogenesis. The name of the process you're probably looking for here is gluconeogenesis: http://en.wikipedia.org/wiki/Gluconeogenesis http://en.wikipedia.org/wiki/Gluconeogenesis
- foobarbazqux 13y agoRight, ok. Thanks. It's related to but distinct from ketosis / ketogenesis, and I was conflating them.