Question about calories consumed vs. exercise calories burne

Rworthy
Rworthy Posts: 271 Member
edited September 22 in Food and Nutrition
So my fitness "expert" told me that if you aren't eating enough calories, your body will digest muscle instead of fat. My question is this: Say I exercise on any given day and burn 700 calories exercising. Does that mean I should have eaten at least 700 calories that same day BEFORE exercising? Let's say I only ate about 300 calories, then exercised and burned 700...does that mean the exercise was a waste and I'm actually losing muscle? Or does it not happen that fast? I'm confused. I have never consumed more calories than I have burned during exercise on any given day before exercising. Am I just working backwards? Any help is appreciated :)

Replies

  • maffu00
    maffu00 Posts: 17
    I have been wondering the same thing. What if your lifting weights? Wouldn't you then be burning muscle tissue, but at the same time gaining it? Thats so confusing.

    Edit: Were you using 300 calories as just an example? Or do you really only eat 300 calories a day? If so, you are (most likely, everyone is different though) putting your body into starvation mode because you body realizes its not getting enough energy, so it starts to store it., which will greatly slow down your metabolism and put a screeching halt on your weight loss.
  • Egger29
    Egger29 Posts: 14,741 Member
    Hey there,

    First off to say "your body will digest muscle" is inaccurate. that being said however you do want to ensure your diet has enough calories in order to Maintain your current lean mass.

    With extreme diets, (I.E. drastic calorie reductions) the body tends to lose alot of water which is an essential component of your Muscle tissue and lean Mass.

    So with this in mind, you want to make sure your daily intake is at least enough to maintain your current level of lean mass.

    When this part of your body is being fed it's needs (and additionally maintained with some form of resistance training), the calorie deficit is then geared more towards the remaining body fat which is where you want any losses to come from.

    On the same line, if your body isn't getting enough calories (I.e. energy), the body's metabolism slows to a crawl to concerve whatever evergy stores you have. This is why extreme dieting never works in the long run.
  • Rworthy
    Rworthy Posts: 271 Member
    I usually only have about 300 calories consumed with breakfast and/or small lunch before exercising. I usually burn 500-800 calories exercising.

    I eat way more than 300 calories total...just not before exercising.
  • Rworthy
    Rworthy Posts: 271 Member
    Hey there,

    First off to say "your body will digest muscle" is inaccurate. that being said however you do want to ensure your diet has enough calories in order to Maintain your current lean mass.

    With extreme diets, (I.E. drastic calorie reductions) the body tends to lose alot of water which is an essential component of your Muscle tissue and lean Mass.

    So with this in mind, you want to make sure your daily intake is at least enough to maintain your current level of lean mass.

    When this part of your body is being fed it's needs (and additionally maintained with some form of resistance training), the calorie deficit is then geared more towards the remaining body fat which is where you want any losses to come from.

    On the same line, if your body isn't getting enough calories (I.e. energy), the body's metabolism slows to a crawl to concerve whatever evergy stores you have. This is why extreme dieting never works in the long run.

    So, to rephrase my question: Does it matter if you eat back your exercise calories before or after you exercise? SHOULD you have consumed AT LEAST the amount of calories you will burn during exercise BEFORE your exercise routine? Does this matter?
  • maffu00
    maffu00 Posts: 17
    When this part of your body is being fed it's needs (and additionally maintained with some form of resistance training), the calorie deficit is then geared more towards the remaining body fat which is where you want any losses to come from.

    Ok, thank you. So is it ok to burn more calories in a day than you consume? For example, lets say someone eats a total of 1400 calories, but they burn off atleast 1500 with just exercise, is that dangerous?
  • Rworthy
    Rworthy Posts: 271 Member
    When this part of your body is being fed it's needs (and additionally maintained with some form of resistance training), the calorie deficit is then geared more towards the remaining body fat which is where you want any losses to come from.

    Ok, thank you. So is it ok to burn more calories in a day than you consume? For example, I eat a total of 1400 calories, but I burn off atleast 1500 with exercise, is that dangerous?

    I am not sure. I don't really trust what that other guy said above. I know your body burns X amount of calories just being alive. If you eat less than that, you should lose weight. But I think a deficit of more than 1,000 calories, which is what would result in your scenario above, is dangerous!
  • nursevee
    nursevee Posts: 344 Member
    No, you don't need to consume all those calories before you workout. I mean, I workout in the morning and it would be a huge challenge for me to eat THAT much (without feeling ill) prior to exercising. Overall your body needs to have enough calories to sustain itself. Your metabolism keeps pumping as long as it is regularly "topped up." This means that throughout the course of the day you should be giving it regular nutrition. Work out your BMR (number of calories burned if you were to do nothing). Factor in the amount you eat on a daily basis. If you run into a deficit, you need to "fuel up" more regaulrly. If you don't, your metabolism will slow down and your body will consume muscle as fuel. On top of your normal daily cal's, you should eat back approx 50% of the exercise cal's you burn. It needs to be slow and steady and regular, hence the importance of snacks.
  • lordofultima
    lordofultima Posts: 293
    You can cannibalize muscle if you don't eat enough and you exercise too much. What causes this is highly debatable of course, but the fact is that most people losing larger quantities of weight (over 2 lbs. a week) tend to lose a certain percentage of muscle along with the fat.

    I've been losing fat and gaining muscle simultaneously, so my scale weight stays relatively the same. All has to do with consuming proper calories, and making sure I get plenty of protein so my muscles can actually rebuild after being broken down with intense resistance training.

    You HAVE to eat less than you burn in a day, otherwise it's physically impossible to lose weight.
  • fxst78
    fxst78 Posts: 221 Member
    When this part of your body is being fed it's needs (and additionally maintained with some form of resistance training), the calorie deficit is then geared more towards the remaining body fat which is where you want any losses to come from.

    Ok, thank you. So is it ok to burn more calories in a day than you consume? For example, lets say someone eats a total of 1400 calories, but they burn off atleast 1500 with just exercise, is that dangerous?

    VERY DANGEROUS!!!

    You should have a defecit below your BMR, not below ZERO!!!!

    You are in effect taking in -100 calories a day. that is extremelly dangerous.
  • fxst78
    fxst78 Posts: 221 Member

    You HAVE to eat less than you burn in a day, otherwise it's physically impossible to lose weight.

    Yes but remember you "burn" (dependiong on the person) 1500 odd calories a day just being alive, so to exercise another 1500 calories and only eat 1400 calories is very very dangerous.
  • lordofultima
    lordofultima Posts: 293
    lol guess I just misunderstood. I definitely didn't mean to burn every calorie that you consume, only to be under your TDEE, around your BMR.
  • Rworthy
    Rworthy Posts: 271 Member
    No, you don't need to consume all those calories before you workout. I mean, I workout in the morning and it would be a huge challenge for me to eat THAT much (without feeling ill) prior to exercising. Overall your body needs to have enough calories to sustain itself. Your metabolism keeps pumping as long as it is regularly "topped up." This means that throughout the course of the day you should be giving it regular nutrition. Work out your BMR (number of calories burned if you were to do nothing). Factor in the amount you eat on a daily basis. If you run into a deficit, you need to "fuel up" more regaulrly. If you don't, your metabolism will slow down and your body will consume muscle as fuel. On top of your normal daily cal's, you should eat back approx 50% of the exercise cal's you burn. It needs to be slow and steady and regular, hence the importance of snacks.
    Okay so you're closest to answering my question. I did some calculating and I think MFP is off by about 1,000 calories as far as how many calories I should be eating.

    My BMR > How many calories my body burns to stay alive = 1769.2
    My daily caloric needs > How many calories I burn daily (estimate) based on my level of physical activity = 2742
    Calories I should consume to lose weight > Daily caloric needs minus (-) 500-1000 calorie deficit = Between 1742 - 2192

    Question: Do I then factor in exercise calories burned and add that to my Calories to be consumed? Or as long as I stay between 1742 - 2192 I should be all good, whether or not I exercise on that day? This is daunting....
  • Egger29
    Egger29 Posts: 14,741 Member
    Hey there,

    No, it doesn't matter when you eat back your calories so long as you are getting your necessary total for the day.

    If you're using the tracker on here, the counter incorporates exercise in with your meals to account for your daily needs.

    Your daily overall deficit shouldn't be more than 500 calories per day however as healthy weight loss is at about 1lb per week. (3600 calories in a lb).

    The reality isn't as simple as the mathematical calculations however as there are a ton of factors and involved in each individuals lifestyle.

    To better clarify my comment from before allow me to illustrate the following Example (Reference to Susan Kleiner's Power Eating)

    Basically speaking, each lb of lean mass requires 11-12 calories for daily maintenance. For simplicities sake, let's assume a 200 lb individual who with 25% body fat.

    To avoid breaking down the lean mass (150 lbs or 75% of 200)...the body requires a daily consumption of 1650 Calories (150 x 11). This is a Basic requirement for someone who is doing nothing...i,e, 24 hrs lying prone.)

    With that in mind, that individual would need to consume at least 1650 Calories, each day to maintain the amount of healthy lean mass in their body.

    Your activity level is then added into the equation which is a general percentage based on your personal lifestyle. This is a variable depending on the individual person's activity level, sex and age.

    The result is an individual daily requirement for yourself personally depending on your circumstances.

    As you increase the amount that you exercise, you also increase the amount of daily calories you require to maintain a healthy balance.

    These calories are not required immediately following the specific exercise, but are accounted over the course of an entire day.
  • Egger29
    Egger29 Posts: 14,741 Member
    Your BMR is 1769.2.

    Add to that your number of calories burned daily. (For simplicities sake lets use 1000)

    That makes your daily caloric requirement to be 2769 (BMR + Exercise Requirements)

    If you're looking to lose, simply plan your diet at a figure about 500 calories less than this amount. or 2269 / day

    That gives you a daily intake deficit of 500 Calories / day assuming your exercise requirements are the same.

    As your exercise requirements are a variable, this will fluctuate your daily needs from day to day.
  • Rworthy
    Rworthy Posts: 271 Member
    Thanks for that. With your calculations, I should eat about 1631 plus at least 50% of what I burned exercising (thanks to help from a previous post). That puts me at about 1981, which is close to the other calculations. I guess I thought there were some guidelines on how much to eat before exercising. I'm exercising off more than double what I have eaten that day (at that time). After exercising, I feel weak, nauseous and get headaches. I can't get more calories in fast enough. I think eating more before exercising will help me feel better, but from what you are all saying, it won't help or hinder fat burning. :/
  • Rworthy
    Rworthy Posts: 271 Member
    FYI This is a pretty good article. I feel better now. http://health.msn.com/fitness/articlepage.aspx?cp-documentid=100146039&page=1
  • Egger29
    Egger29 Posts: 14,741 Member
    Yes. Good Article.

    Consider that Calorie = Energy so if you expend energy in any context you need to re-fuel to keep going.

    Studies have shown that intaking Protein/Carb mix meal of some kind withing 30-90 minutes of your workout has an enhanced benefit of re-fuelling the body at the cellular level.

    That being said, it's not required that you have as many calories as you just burned. More importantly is something quick and easily digested to get it into your system, be it a Protein shake, fruit smootie, peanut better sandwhich...whatever works for you and fits your personal meal plan.

    It's a lifestyle thing for the most part as each individual's needs and schedules are differernt for both exercise and eating.
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