A ‘calorie’ is a measure of the ‘work’ done. In physics, Work = Force x Distance. Here on earth (because of gravity), you can pretty much equate “Force” with “Weight”. So a calorie will move a certain amount of weight (like your body, or a dumbbell) a certain distance (like a mile, or from the floor to over your head).
All foods provide calories that we use to perform work (i.e. move weight over a distance). Carbohydrates and Proteins provide about the same amount: 4 calories per gram. Fats provide more: 9 calories/gram. (An easy way to calculate the calories in a food is to remember “PFC 494”. To calculate calories, add the grams of Protein x 4, Fat x 9 and Carbs x 4.)
Even though all foods can be used for calories, they can be used for other things too - and they get converted into calories in different ways.
· Carbs are only used to generate calories.
· Proteins provide the building blocks for life: to create muscle, tissue, organs, bones, nerves, etc. Your body will also burn proteins (to make calories) if there aren’t any carbs around or if it has extra proteins, but that’s kind of like burning the furniture to heat the house. It’s your body’s last choice.
· Fat stores calories. Your body can get calories directly from the fats you eat – or from the fat you have saved up all around your body.
Calories in = Calories out. Always. That’s just the way it is (back to the laws of physics.) A calorie, is a calorie, is a calorie: Calories are all the same – regardless of where they come from or when you eat them – and there is only one way to get rid of them: by doing work! If you eat too many, your body stores them as fat. If you don’t eat enough, your body will get the calories it needs from stored fat.
Dieting, although not easy, is simple: If you use more calories (by moving weight over a distance) than you take in as food, you lose weight. Period. Simple.
Myths about calories:
· Myth #1: Eating before bed-time will make you fat. It won’t - any more than eating at any other time of the day. The laws of physics on this (Work=Force x Distance) make no mention of “time of day”.
· Myth #2: It matters how fast I run or how long I work out. Actually, it doesn’t matter. There is no mention of ‘time’ or ‘speed’ in the calorie equation either – so, interestingly, the number of calories your burn has nothing to do with how long or how fast exercise. It’s all about the weight and distance. In other words, running a mile burns as many calories as walking a mile. Or, when burning calories with weights, the amount of weight matters and the number of reps matter – but how fast you do it doesn’t matter. Of course, you cover more distance if you run fast, but it takes less time – so they cancel each other out.
· Myth #3: Calories from fat are bad. No, they are the same as all other calories. Fat just has a lot of them in it.
Fun Facts:
- Other familiar terms that measure “calories” include Watts, B.T.U’s, Horse Power, Joules, Foot-lbs, etc.
- There is ONE other way to burn calories: By creating HEAT. So - do you burn more calories in the winter? Yes! But, compared to the calories you expend doing work (part of which creates heat too), they are nearly insignificant - and pretty constant except when you are moving.
Dear Denny,
ReplyDeleteI love your Blog. I am looking forward to more pearls...I do want to challenge you on one claim. Re: Myth #2. you state that time is not a factor in calorie burning. I must disagree. (Remember I do not have an engineering degree). If I run the mile while you walk that same mile, we have consumed the same amount of calories. But, while you are still walking, I am off to something else that burns more calories. So, in a 24 hour day, I run plus take a nap in an hour, while you just walk. Haven't I burned up more calories in the hour?
Curious in Golden Valley
Mike - Time is not in the "work" equation - only Distance and Weight. Moving a rock up 100 feet uses the same amount of energy regardless of how long it takes. However, you ARE right that you can burn more calories in a day if you run - you have created more DISTANCE in a day, not more TIME. It is also true that you are burning calories napping on the couch while I am finishing my walk, but not many more. If that weren't true, there'd be a "Nap the Calories Off" blog somewhere. (Actaully, there probably is one somewhere, but don't believe everything you read.) Thanks for the question!
ReplyDeleteThis blog is great -- you are a great writer, Den! But I also have to say Myth # 2 is SO counter to what I've been brainwashed to believe through diet books, gym memberships, etc...I'm not quite with you yet. I did this thing at Lifetime fitness a while back where they put a respirator on me and measured out exhertion stages and when I went into anearobic vs aerobic burn... you burn calories at different rates depending on the fitness level and degree of exhertion. Isn't there more to this in terms of BioPhysics (not just straight ol' physics?) Anyway, I totally love this blog. Rock on!
ReplyDeleteDenny,
ReplyDeleteGreat idea for a Blog!!
Peter
I love this question! You HAVE been brainwashed – and for exactly the reasons you listed. The “anaerobic/aerobic burn” sells LOTS of books, “metabolism” tests, software, memberships and gadgets. (Eventually, this stuff will end up in the Bakken – with the other quackery.) It’s also the first pitch you’ll get from a trainer looking for your business.
ReplyDeleteIt is true that, when you go “anaerobic”, there is a shift in the metabolic pathway that happens because you can’t get enough oxygen to turn glucose into water and CO2. (My next blog-post should probably be about metabolism.) Your body takes shortcuts and converts other sugars (and even fats or proteins) directly into energy. It is less efficient, so that part of the argument is true. The most common shortcut produces lactic acid as a byproduct, causing muscle stiffness. (By the way, lactic acid is also what makes green olives taste so good and comes from the same shortcut – except in the vinegar making process.) Another shortcut, made famous by the ‘Atkin’s Diet’, is ketosis - which comes from the direct conversion of fats into energy that happens when there are no carbs (glucose) around.
Your question is really about efficiency – sort of the biological equivalent to the ‘EPA Estimated Highway Miles”. However, evolution has done a pretty good job of making us all Prius-like in our ability to use energy. Your ‘mpg’ does go down when you are in anaerobic burn, but only by a very small percentage. Other things affect your efficiency too – like your ‘gait’, alcohol or caffeine, muscle mass/type and long endurance exercise. All of them really do pale, however, when compared to the macro energy needed to move weight over a distance.
All-in-all, the shift from the aerobic to an anaerobic pathway has some effect on calorie consumption, but not enough to invalidate the Weight x Distance formula. Keep the books and rest of it though – especially if they keep you going to the gym working out.