If I eat then run am I burning off those calories?

alexastoutxo wrote: »

JeromeBarry1 wrote: »

Your metabolism has an app that you download from the app store to select which of your recent and future meals you designate as the source of energy for your activities. Right?

Well wouldnt that be nice to do lol but no i realize it doesnt do that but i want to know whether the source of energy is coming from that meal as well as my overall calories. Make sense?

It does make sense that a human can want to know, but there's no way any of us can know or say definitively. You are born with a bodily supply of energy in the form of glycogen stored in your tissues, your lean body mass, and lipids stored in your fat cells. You immediately begin consuming energy and a lifetime of mixing new energy with old supplies goes on and on until you stop adding new energy with your death.

This issues around "fasted" or "fed" exercise have only to do with the physical comfort of trying to exercise while also having a belly trying to digest food. Some people find it easier to exercise on an empty belly.

When I was studying metabolism as part of my nursing degree (a while ago now!) we were taught that simple sugars were most readily available for fuel, then complex long chain carbs that are broken with proteins and fats used as a last resort as the body uses them to build muscle and make hormones etc. but then stored energy is converted usable fuel by a process known as gluconeogenisis ... so you can’t really know what morsel of food is fueling you at any given time. Blah blah.

If you are interested in how your body is creating the energy you use on a cellular level for aerobic vs anaerobic respiration (cellular not breathing) you could look up the Krebs cycle for a bit of info.

alexastoutxo wrote: »

sijomial wrote: »

alexastoutxo wrote: »

kommodevaran wrote: »

alexastoutxo wrote: »

kommodevaran wrote: »

Your lunch doesn't sound like a big lunch - how many calories is it, and what's your total daily intake? How many calories did MFP tell you to eat per day? What's your height and weight?

When you eat and exercise has no impact on the amount of calories you burn. Digestion and energy expenditure are not related. Your body burns energy 24/7, not specific calories.

Well i wouldnt say its calorir dense because its only about 290-300 calories but its pretty voluminous. I understand my body is burning calories 24/7 but I'm still confused as to whether the calories I ate from lunch is burned off when I run after eating it?

Size can point to volume too, that's right, but when it comes to weight management, it makes no difference; only calories makes a difference.

If you have a bucket half filled with water, and you pour a glass of water into it, and then you fill the glass from the bucket and drink it, which water are you drinking?

If you're asking whether your run burns off the amount of calories you ate for lunch - maybe.

Well I'm asking more so if I'm atleast burn SOME calories from that meal. Im a long distance runner and I usually run for more than the hour sometimes two on most days but I don't think I burn off those 300 calories from lunch in just one run

Again why does it matter?

Yes you may use some carbs from the meal you just ate - but you will also burn carbs from your glycogen stores.
You will also be burning some intramuscular fat and circulating triglycerides - but not the fat you just ate or your subcutaneous fat.

Is this an exercise fuelling question or a weight loss question?
If the latter then it's a complete irrelevance where your energy (calorie) originally came from - the meal just eaten or the one eaten the day before.
Your weight loss/ fat loss comes down to your calorie balance over an extended period of time.

Or is this an exercise calorie burn question? Trying to estimate how much you burn from running?

I guess it's just a exercise calorie burn question..but another reason why I initially thought of asking this is because I have heard others on here talk about how they eat preworkout snacks before their workouts to use that quick energy as a source for their workouts so that got me thinking whether the meal i just had is also "fueling" my runs.

For your running calorie counts I would suggest using...
https://www.runnersworld.com/tools/calories-burned-calculator

I'm a long distance cyclist so do have an interest in fuelling.... Glucose in particular gets absorbed and used very quickly, hence why energy drinks include it.

My usual rules of thumb are....
For up to 2hrs - nothing except water, possibly electrolytes if hot. We have loads of readily accessible energy onboard already.
2 to 3 hrs - I'll be making up or using sports energy drinks to drink while I ride.
Over 3hrs - I'll be eating something carby beforehand, plus energy drink while riding, plus maybe carby snacks.
Over 4hrs - I'll be taking my eating and fuelling fairly seriously.
Over 5hrs - I'll be planning in detail and preparing over the course of the week. Pre-ride, during ride and also post ride nutrition. Probably fuelling mostly with a glucose/fructose mix to get round the limitation on glucose abortion while exercising (commonly stated as 60g/hour).

Think of it this way:

Say you have a quarter tank of fuel in the engine. (Let's call this Source A) You pump 4/3 a tank in at the gas pump. (Source B ) Then you drive.

Once the gas mixes together in the gas tank, it's both: AB if you will. You can't unscramble the eggs. At any given moment, the engine uses the mixture to fuel the engine.

It's a little more complicated for humans, because we have a process of digestion. Food does digest at different rates (a sugar water solution will be taken up quicker than a cheeseburger) and there is blood glucose levels and so on. But this process is only slightly different.

alexastoutxo wrote: »

So I usually like running after I have my lunch which is a pretty big lunch (tuna wrap, fruit/veggies, some yogurt) and i only wait about 1 hour afterwards then go for a run but since its a larger meal and i only waited an hour, am i burning off those lunch calories? Or no because I didn't let it digest alittle longer? If I'm not, what calories am I burning off then? So many questions but so curious haha but I would appreciate the knowledge on this thanks!

You're just burning calories, period. You burn calories 24/7, not just with exercise. A calorie is just a unit of energy...it doesn't matter if you're burning calories from you lunch or your breakfast or last nights dinner or if you're getting your calories (energy) from body fat...you're just burning calories. You're overthinking...if you are in a calorie deficit, you're going to lose weight...

It's like gas in your car...you put gas in your car and you burn that fuel when your car is on or you are driving...it doesn't matter when you put the gas in your car...all that matters is that there is gas in your car.

You'll use some of it, if it has been digested/metabolized enough to be circulating in your bloodstream already.

Go eat some isotope-labeled glucose and then go work out and live in a metabolic ward for a while. Probably the only way to know for sure.