How much calories i need to burn to lost 1 lbs. of body fat?

  1. as title says
     
  2. jcsd
  3. About 4000.
     
  4. if you use energi and e= mgh and remember that the body is about 75% efficient. you can burn as much calories you want. just by lifting things over your head. which is about 2m.
     
  5. Evo

    Staff: Mentor

    One pound of fat is 3,500 calories. To lose a pound, in essense, you need to eat 3,500 calories less than you need.

    In weight loss, other factors such as metabolism, water held in fat, etc... will affect how quickly and effectively you lose the weight.
     
  6. I saw 3500 on some pediatrics website, and wolfram alpha said about ~4000. Is there a better source?
     
  7. Evo

    Staff: Mentor

    It has always been 3,500 calories since that unit of measurement came into use, to my knowledge.

    http://www.mayoclinic.com/health/calories/WT00011

    http://science.education.nih.gov/su...508/dbalance/reference/dbalance_ref.htm#sec2c

    I have no idea what wolfram alpha is doing to come up with a different value, I have never seen 4,000 calories.
     
  8. i swim twice a week, hike 10 miles every weekend, but still not losing much weight. in fact, i gained 3 lbs since Thanksgiving, wtf

    trying to figure out a realistic workout schedule to stay fit and in shape, ideally i'd like to lose 5~10 lbs
     
  9. Evo

    Staff: Mentor

    How many calories do you consume per day? How many calories do you estimate you burn per day? There are guides all over the internet that will help you calculate your calorie expenditure for certain activities based on your gender, height and weight. There are factors to consider such as metabolism, for example, a person with more muscle will normally burn calories more efficiently than a person with more fat.
     
  10. my typical daily meal intake is like this:

    1 cup of oatmeal in the morning
    1 footlong sandwich with all the bells and wistles (sometimes buffet or hamburger)
    dinner i usually skip, just some fruits and maybe a ramen cup noodle

    i'm a guy in my 30s, weight about 155 lbs, height 5'7''
     
  11. Evo

    Staff: Mentor

    If you are more muscle than fat, that's not a bad weight for your height. Why are you concerned?
     
  12. Drakkith

    Staff: Mentor

    I'm about your height, about the same weight, and I don't work out nearly as much as you do. I'm betting that you are mostly muscle, not fat. So no need to lose any weight!
     
  13. Andy Resnick

    Andy Resnick 5,951
    Science Advisor
    Education Advisor

    Keep in mind that the human body stores energy as fat, which has a dietetic calorie content of 9 kcal/g. Thus, to 'lose a pound of fat' implies that 4032 kcal worth of stored fat is used.

    Now: loss of fat also entails loss of water (the blood that supplies adipose tissue is decreased), 9 kcal/g is the energy content of some sort of fat burned in a calorimeter and may not be truly equivalent to the fat content of adipose tissue and the process of metabolism, energy is not only stored as fat but also glucose, glycogen, and ultimately ATP.

    So, numbers between 3500 and 4000 kcal (or Calories) are *very* reasonable.
     
  14. Evo

    Staff: Mentor

    When you lose weight, you lose glycogen first. You don't burn stored fat first, stored fat is actually the last thing you burn.
     
    Last edited: Dec 14, 2011
  15. Andy Resnick

    Andy Resnick 5,951
    Science Advisor
    Education Advisor

    The body typically has a total of 700 g (3000 kcal) worth of glycogen at any moment- it is a tiny fraction of the total amount of stored energy. Although you do indeed catabolize glycogen first to extract energy, glycogen stores are then replenished by conversion of lipid stores.
     
  16. Evo

    Staff: Mentor

    Correct,
    Mainly I wanted the OP to know that contrary to all off the internet "burn fat instantly" hype that stored fat is the last to go. I'm a woman, we know these things. :tongue2:
     
  17. Andy Resnick

    Andy Resnick 5,951
    Science Advisor
    Education Advisor

    I think I'm offended by your blatant sexism ;)
     
  18. Drakkith

    Staff: Mentor

    Be offended later...I need to write this down...Evo...Woman...Fat...got it.
     
  19. Evo

    Staff: Mentor

    Drakkith...member...soon to be non-member... :tongue2:
     
  20. Drakkith

    Staff: Mentor

    I'm confident I can outrun your-[Error: Member Deleted]
     
  21. Evo

    Staff: Mentor

    :biggrin: :rofl:
     
    Last edited: Dec 15, 2011
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