How does calorie deficit work?

theron12
theron12 Posts: 60 Member
edited November 2024 in Health and Weight Loss
I understand the process that 3500 calories equals a pound of fat. So 500 calories under maintainance over a week would be 1 pound loss or 1000 calories under maintainance is 2 pounds loss. My question is this: For example say someone is on a 2000 calorie diet. 2000 X 7 days a week is 14,000 calories. So that's how many calories I have for the week In order to lose weight. Can you eat more or less calories per day & still achieve the same goal? so say I only ate 1500 calories a day for 6 days that week, that would be 9000 calories. So technically you still have 5000 calories you could eat. So on that 7th day would that person still lose weight if they were to consume the whole 5000 calories in that one day? Or does it not work this way? Someone care to explain this to me? Thanks!

Replies

  • NorthCascades
    NorthCascades Posts: 10,968 Member
    Yeah it basically works like you said. They body doesn't process calories on a 24 hour schedule. You can go over one day and under the next.
  • seska422
    seska422 Posts: 3,217 Member
    If your maintenance calories are 2500, then yes as an average over time. Weight loss isn't linear. Many people look at their total calories over the week and spread them out however they wish. It's the total deficit that matters.

    If I have an average of a 500 calorie deficit over a couple of months, then I'll lose an average of 1 pound per week. If I don't lose that much, then I need to look at how I'm counting my calories in and calories out because I'm off in my counting somewhere.
  • tinkerbellang83
    tinkerbellang83 Posts: 9,147 Member
    edited June 2017
    theron12 wrote: »
    I understand the process that 3500 calories equals a pound of fat. So 500 calories under maintainance over a week would be 1 pound loss or 1000 calories under maintainance is 2 pounds loss. My question is this: For example say someone is on a 2000 calorie diet. 2000 X 7 days a week is 14,000 calories. So that's how many calories I have for the week In order to lose weight. Can you eat more or less calories per day & still achieve the same goal? so say I only ate 1500 calories a day for 6 days that week, that would be 9000 calories. So technically you still have 5000 calories you could eat. So on that 7th day would that person still lose weight if they were to consume the whole 5000 calories in that one day? Or does it not work this way? Someone care to explain this to me? Thanks!

    Yes you can do it this way if that suits you better, this is essentially what those doing 5:2 intermittent fasting do (Usually 2 days eating 500-600 calories and 5 eating at Maintenance level). However, it may not be suitable for everyone.

    You can also look at your calories as a weekly average by tapping on nutrition at the bottom of your diary and viewing the calories tab and changing the view from Daily to Weekly and choosing Net Calories.

    You may find however that if you're consuming a lot of calories in one day that you retain a lot of water if your macro intake is significantly different from the rest of the week.
  • Tacklewasher
    Tacklewasher Posts: 7,122 Member
    In theory, yes. In reality a week is too short of a time frame for the numbers to come out this way. So, if you track perfectly accurately (we don't) and fit the models exactly (we don't) you should lose at that rate. But the scale will fluctuate based on diet (sushi and the sodium in the soy sauce makes me gain 2 lbs or so), when you last went and a whole bunch of other random things that weight does not come off in a straightforward fashion.

    For example, this month I lost ~ 5 lbs so far. But it all dropped off in the last week. I'm trying for 1.5 lbs per month, so I'm pretty close to my goal loss for the month, but week by week is all over the map.

    But you have the right idea. I look more at my rolling 1 week over/under calorie goal than the daily one. I have up days and down days, but try to hit the weekly goal.

    May 31-June 6 I was over by 27 cals, but had one day over 800 cals.
    Next week over by 678 (one day over by 1000, but I knew this)
    Next week over by 17
    Next week under by 529.

    That ties in pretty well with what I've lost this month.

    Now understand that the models etc. are estimates and over time you should track your net calories vs. your actual weight loss to see if the models fit you. If you lose more than expected, eat more, less than expected, eat less. If you are not losing near what the models say, then look to see if your logging is close to accurate.
  • theron12
    theron12 Posts: 60 Member
    Thanks for all the replies everyone! I'm not planning on trying this out personally but I was just curious. All of your answers definitely help!
  • cwolfman13
    cwolfman13 Posts: 41,865 Member
    You have to determine your TDEE (Total Daily Energy Expenditure)...these are the calories (energy) you require to exist, go about your day to day, and fuel exercise, etc. These are your maintenance calories. There are any number of calculators that can help you ESTIMATE your TDEE.

    MFP utilizes the NEAT (Non Exercise Activity Thermogenesis) method whereby it determines your "maintenance" as per your day to day activity without any exercise...exercise activity is accounted for after the fact when you log it and get additional calories to eat to account for that otherwise unaccounted for activity.

    If you're using this calculator, it's done the math for you...your calorie target is your deficit calorie target for weight loss...there's really not much to think about other than making adjustments per real world results...the calculator has done the work for you.

    My TDEE is around 2800 calories...the includes my BMR (calories required to exist), my day to day, and my regular exercise...so if I eat 2,300 calories, I'm in a 500 calorie per day deficit.

    And yes, you can look at things from a weekly perspective...you don't "reboot" at midnight...energy balance or lack thereof happens on a continuum.
  • StaciMarie1974
    StaciMarie1974 Posts: 4,138 Member
    A body uses energy daily. The functions of keeping you alive (breathing, heart beating, brain activity, etc.) as well as moving you thru your day. The basic living functions can be summarized by BMR (basal metabolic rate) and can be estimated based on gender, height, weight, age. The 'moving you thru your day' part is the energy your body uses for actual movement, so your daily activities/hobbies/job factor in. This is why MFP asks you to choose an activity level.

    MFP estimates the total of BMR and daily activity when you set up your profile. You can also use a search engine to find an online BMR calculator. Multiply it by 1.25 if you're fairly sedentary. Or multiply it by 1.3-1.4 if you're lightly active/fairly active.

    That is approximately how many calories your body uses NOT counting intentional exercise. From this total, deduct 500 and eat that to average 1 pound per week.

    Such as if your BMR is 1500 and you are fairly sedentary (job is mostly sitting, no hobbies that keep you moving) then you could estimate your body uses about 1875 per day. Eating 1375 will average 1 pound per week.
  • Chadxx
    Chadxx Posts: 1,199 Member
    Yep, this is the idea behind budgeting your calories and lots of folks here do it all the time although usually not to that extreme.
  • StaciMarie1974
    StaciMarie1974 Posts: 4,138 Member
    Was not paying any attention to you being a guy. :) Gender is a factor and guys tend to have higher BMR, TDEE than gals. So my example of a 1500 BMR is going to be lower than YOUR BMR.
  • vismal
    vismal Posts: 2,463 Member
    The theory behind what you are doing is fine. In practice, you're going to hate eating 1500 calories 6 days a week. Maybe not at first, but believe me, you eventually will! If you don't hate life eating 1500 calories a day, I'd closely review how diligent you are at tracking (are you weighing all your food on a food scale? If not, start!). I have encountered very few men capable of eating so little for any extended period of time. Those that have been able to do it always report that it sucked really bad. Maybe a better strategy would be to shave 100 or 200 calories from each day to add to your higher calorie day. It still gives you that one day of flexibility without making the rest of the week really suck.
  • NorthCascades
    NorthCascades Posts: 10,968 Member
    Also, don't take this too far. I mean if a week is good, a month isn't better.
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