Calories in vs. Calories out at the beginning of weight loss journey
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beth0277
Posts: 217 Member
I understand the concept of calories in vs calories out but can someone explain why most people lose weight more quickly at the beginning of their weightloss journey? Take me for example...I've recently started and have at least 50 pounds to lose. My TDEE is around 2080, per my fitbit and calculations I've done online say I should be in between 1990-2200 so I think I'm pretty accurate there. I've been eating 1500 calories a day and hope to burn around 500 calories a day which would put my daily deficit at 1000 calories, so around 2 pounds a week. That math makes sense to me.
However, the last 2 days I've stuck to my calorie goal however because of back-to-school and other things going on, did not burn more than maybe 200 more than my TDEE. So that puts me at a deficit of around 700/day for the last 2 days. Monday I lost .8 pounds and yesterday I lost 1 pound. How is this explained? I'm not complaining and I know people usually lose faster at first, but I'm just trying to make sense of it from a scientific standpoint. I haven't had the calorie deficit to lose that amount of weight. Just curious!
However, the last 2 days I've stuck to my calorie goal however because of back-to-school and other things going on, did not burn more than maybe 200 more than my TDEE. So that puts me at a deficit of around 700/day for the last 2 days. Monday I lost .8 pounds and yesterday I lost 1 pound. How is this explained? I'm not complaining and I know people usually lose faster at first, but I'm just trying to make sense of it from a scientific standpoint. I haven't had the calorie deficit to lose that amount of weight. Just curious!
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Replies
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If you mean fast #s lost in the beginning: there can be shifts in water weight, as you deplete your glycogen stores. (Happens naturally when you eat at a calorie deficit and glycogen holds water. So reduced glycogen means less water in your body.)
If you mean why does one typically lose more when they have more to lose ('easier' to lose the first 5 than the last 5) its because when you start out your TDEE is higher due to being heavier. If you're experiencing a TDEE of 2080 now, then cutting off 500-750 is doable. If you're smaller and have a TDEE of 1700-1800, you can't do the same deficit.
For what its worth, the deficit/work you do today may not be immediately shown on the scale tomorrow. Some things take more time, and water weight will often be a factor. Water weight has quick tendencies but fat loss is more gradual. In my opinion!
Now this does not mean that everyone will always see a drop in the first 1-2 weeks. Kind of depends on what all you change. If you started eating at a deficit about the same time as starting a new workout routine and TOM bloating, you'd probably see a water weight/increase before seeing a drop weeks later.
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I've recently started and have at least 50 pounds to lose.
I've been eating 1500 calories a day and hope to burn around 500 calories a day which would put my daily deficit at 1000 calories, so around 2 pounds a week. That math makes sense to me.
Wait, you're eating 1,000 net calories per day?! A healthy, sustainable loss is .5 lb. per week for every 25 lbs. you're overweight, and chronic undereating will not make you lose 2 lbs. per week.
Your Fitbit burn is TDEE. If you eat at a reasonable deficit from that, you will lose weight. Connect your accounts at http://www.myfitnesspal.com/fitbit
Set your goal to .5 lb. for every 25 lbs. you're overweight: http://www.myfitnesspal.com/account/change_goals_guided
Enable negative calorie adjustments: http://www.myfitnesspal.com/account/diary_settings
You can learn more in the Fitbit Users group: http://community.myfitnesspal.com/en/group/1290-fitbit-users0 -
I haven't got time now to explain your question at length but i can say this. Usually people lose a lot at the very beginning becuase suddenly they are not overeating and iwth that, you lose a whole lot of water. The reason for that is carbs are stored as glycogen in your muscles. If you suddenly reduce your carbs, you will automatically lose a lot of water. But i think it may possibly come from elsewhere too. Maybe because suddently you have less salt in yoru system. Salt retains water so less salt means you won't retain so much water.
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editorgrrl wrote: »I've recently started and have at least 50 pounds to lose.
I've been eating 1500 calories a day and hope to burn around 500 calories a day which would put my daily deficit at 1000 calories, so around 2 pounds a week. That math makes sense to me.
Wait, you're eating 1,000 net calories per day?! A healthy, sustainable loss is .5 lb. per week for every 25 lbs. you're overweight, and chronic undereating will not make you lose 2 lbs. per week.
Your Fitbit burn is TDEE. If you eat at a reasonable deficit from that, you will lose weight. Connect your accounts at http://www.myfitnesspal.com/fitbit
Set your goal to .5 lb. for every 25 lbs. you're overweight: http://www.myfitnesspal.com/account/change_goals_guided
Enable negative calorie adjustments: http://www.myfitnesspal.com/account/diary_settings
You can learn more in the Fitbit Users group: http://community.myfitnesspal.com/en/group/1290-fitbit-users
Yes. MFP actually recommends I eat less than that. I set my own calories and am comfortable at 1500 calories/day and feel that it is sustainable. I've had trouble binging in the past when I try to eat less than 1500. I think working out moderately and burning 300-500 most days of the week (an hour walk I will burn close to 300) is not extreme AT ALL. I'm actually trying to do something that I know is sustainable and feel that this is. I eat a lot of healthy food in those 1500 calories.0 -
The glycogen/salt thing makes sense. Like I said, not that I'm complaining, I'm just a numbers/science type of gal so I wondered how it worked.0
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Unfortunately, the numbers in the energy equation, CICO, never work out in practice like they do on paper. There are several reasons. First the number we use for calories burned a day is an estimate. Even with fitness tracking software, it's an estimate. Our calories consumed per day is another estimate. Depending on how accurate you track (do you weigh everything you eat on a scale? If you don't you should! Measuring cups DON'T count! They are for liquids only) that count can be anywhere from a little off, to nowhere even in the ballpark. Add to that water fluctuations, the weight of undigested food in the stomach, and about a million other factors and whatever rate of loss you came up with on paper is thrown completely out the window. Fortunately, even though we can never track it exactly, the energy equation is quite real! What we do know is, that if over the course of several weeks you are not losing weight, you are eating too much. Day to day and even weekly fluctuations in weight are meaningless. You should weigh daily, take an average of the daily weights after a week, then after a month plot those averages. There should be a downward trend. If not, your calorie goal is either too high, or you aren't tracking accurately and need to work on that.The glycogen/salt thing makes sense. Like I said, not that I'm complaining, I'm just a numbers/science type of gal so I wondered how it worked.
The reason people lose more in the beginning is that they usually have full glycogen stores and more margin of error for inaccurate tracking. As you lose weight, glycogen depletes, and the amount of error you can tolerate with your count goes down. When you are close to goal, your margin of error is quite low. This is why some people struggle greatly with the "last few lbs".0 -
Unfortunately, the numbers in the energy equation, CICO, never work out in practice like they do on paper. There are several reasons. First the number we use for calories burned a day is an estimate. Even with fitness tracking software, it's an estimate. Our calories consumed per day is another estimate. Depending on how accurate you track (do you weigh everything you eat on a scale? If you don't you should! Measuring cups DON'T count! They are for liquids only) that count can be anywhere from a little off, to nowhere even in the ballpark. Add to that water fluctuations, the weight of undigested food in the stomach, and about a million other factors and whatever rate of loss you came up with on paper is thrown completely out the window. Fortunately, even though we can never track it exactly, the energy equation is quite real! What we do know is, that if over the course of several weeks you are not losing weight, you are eating too much. Day to day and even weekly fluctuations in weight are meaningless. You should weigh daily, take an average of the daily weights after a week, then after a month plot those averages. There should be a downward trend. If not, your calorie goal is either too high, or you aren't tracking accurately and need to work on that.The glycogen/salt thing makes sense. Like I said, not that I'm complaining, I'm just a numbers/science type of gal so I wondered how it worked.
The reason people lose more in the beginning is that they usually have full glycogen stores and more margin of error for inaccurate tracking. As you lose weight, glycogen depletes, and the amount of error you can tolerate with your count goes down. When you are close to goal, your margin of error is quite low. This is why some people struggle greatly with the "last few lbs".
Listen to this0 -
Glycogen. Glycogen is stored in your liver and muscles along with 3-4 grams of water on a weight/weight basis. People typically can store a maximum of 500 grams of glycogen (with 1,500 - 2,000 grams of water). Glycogen is a carbohydrate and thus contains 4 calories per gram. It takes roughly 400 calories to burn through 100 grams of glycogen with 300 - 400 grams of water. One pound is approximately 450 grams.
So a deficit of 400 calories is enough to lose one pound of glycogen hydrate. There you go!0 -
Before you start a calorie deficit, you are probably eating at a surplus (as in, you've been slowly gaining weight). So your TDEE is 2100-ish, and you've been eating 2200 calories on average, let's say. So you have full glycogen stores (since the body stores water and glycogen when you are eating at a surplus) and your stomach and intestines are full of a couple day's worth of 2200 calories of food.
Then the next day you start eating 1500 calories for a couple days. Your water and glycogen stores deplete and you now only have a couple days of 1500 calories worth of food in your system. BAM, more weightloss than can be accounted for by calorie deficit alone.0 -
editorgrrl wrote: »I've recently started and have at least 50 pounds to lose.
I've been eating 1500 calories a day and hope to burn around 500 calories a day which would put my daily deficit at 1000 calories, so around 2 pounds a week. That math makes sense to me.
Wait, you're eating 1,000 net calories per day?! A healthy, sustainable loss is .5 lb. per week for every 25 lbs. you're overweight, and chronic undereating will not make you lose 2 lbs. per week.
Your Fitbit burn is TDEE. If you eat at a reasonable deficit from that, you will lose weight. Connect your accounts at http://www.myfitnesspal.com/fitbit
Set your goal to .5 lb. for every 25 lbs. you're overweight: http://www.myfitnesspal.com/account/change_goals_guided
Enable negative calorie adjustments: http://www.myfitnesspal.com/account/diary_settings
You can learn more in the Fitbit Users group: http://community.myfitnesspal.com/en/group/1290-fitbit-users
Yes. MFP actually recommends I eat less than that. I set my own calories and am comfortable at 1500 calories/day and feel that it is sustainable. I've had trouble binging in the past when I try to eat less than 1500. I think working out moderately and burning 300-500 most days of the week (an hour walk I will burn close to 300) is not extreme AT ALL. I'm actually trying to do something that I know is sustainable and feel that this is. I eat a lot of healthy food in those 1500 calories.
MFP is also designed for you to "eat back" the calories you burn through exercise so that your net calorie consumption doesn't go below what you need to sustain health and energy. If you are burning 500 calories a day through exercise, you should consider replacing those because a net of 1,000 is low.0 -
Actually according to a recent mfp blog post, mfp doesn't recommend eating back exercise calories if you're losing. Also exercise calories are overestimated by mfp. I've gone days burning more calories than I've eaten, at least according to mfp, and i wasn't starving or exhausted or anything, I felt entirely normal.
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The 'net' also depends on what you set your goal to.
If you have a projected TDEE of 2100
*and set for 1 pound per week loss, you'll be told to eat 1600. If you exercise for 300 and eat 1600, you'll have a net of 1300. If you eat 300 more, MFP says you're dead on. Net 1600.
*and set for 2 pounds per week loss, you'll be told to eat 1200*. If you exercise for 300 and eat 1200, you'll have a net of 900. If you eat 300 more, MFP says you're dead on. Net 1200.
The same person can change their 'net' by changing their weight loss goal. How can one be wrong and one be right? Only if the person feels eating at one level vs the other is better for their own goals, needs.
If your TDEE is ~2100 then eating ~1500 should be fine, assuming you feel energetic and such. Note: TDEE includes all calorie burn so regular lifestyle and exercise. So if you're working out and/or moving more in general, you're increasing your TDEE.
*If MFP's expected TDEE less your deficit goal goes too low, you'll get a bottom line 1200/day calorie recommendation.
So setting your own goal to 1500 and exercising for 300-500 would create a 'net' of 1200-1000 but net is meaningless term ultimately.0 -
Actually according to a recent mfp blog post, mfp doesn't recommend eating back exercise calories if you're losing. Also exercise calories are overestimated by mfp. I've gone days burning more calories than I've eaten, at least according to mfp, and i wasn't starving or exhausted or anything, I felt entirely normal.
Which blog post are you referring to? This seems like some one-size-fits-all advice. I can't imagine they truly intended for people to net under 1,000 calories for extended periods.0 -
I understand the concept of calories in vs calories out but can someone explain why most people lose weight more quickly at the beginning of their weightloss journey?.....
because not all weight on the scale is fat. If you are eating less, you would obviously have less inherent waste in your system. also, when you drop your energy consumption, you start to deplete your glycogen stores...basically water...so you're essentially losing a bunch of water weight when initially cut calories.0 -
The truth is that nobody knows. They're not even sure what, exactly, triggers the fat loss.
I know that, at least for me, there is something about kicking off weight loss that makes me lose quicker for a while before it slows down. The more I'm at this, the more I think that the people who advise six months of losing followed six months off...they may have a point. It's just hard to quit when you're losing, lol.
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The truth is that nobody knows. They're not even sure what, exactly, triggers the fat loss.
I know that, at least for me, there is something about kicking off weight loss that makes me lose quicker for a while before it slows down. The more I'm at this, the more I think that the people who advise six months of losing followed six months off...they may have a point. It's just hard to quit when you're losing, lol.
Whu? The calorie deficit is. Conservation of energy and all that jazz.0 -
janejellyroll wrote: »Actually according to a recent mfp blog post, mfp doesn't recommend eating back exercise calories if you're losing. Also exercise calories are overestimated by mfp. I've gone days burning more calories than I've eaten, at least according to mfp, and i wasn't starving or exhausted or anything, I felt entirely normal.
Which blog post are you referring to? This seems like some one-size-fits-all advice. I can't imagine they truly intended for people to net under 1,000 calories for extended periods.
https://blog.myfitnesspal.com/ask-the-dietitian-should-i-eat-back-my-exercise-calories/0 -
janejellyroll wrote: »Actually according to a recent mfp blog post, mfp doesn't recommend eating back exercise calories if you're losing. Also exercise calories are overestimated by mfp. I've gone days burning more calories than I've eaten, at least according to mfp, and i wasn't starving or exhausted or anything, I felt entirely normal.
Which blog post are you referring to? This seems like some one-size-fits-all advice. I can't imagine they truly intended for people to net under 1,000 calories for extended periods.
https://blog.myfitnesspal.com/ask-the-dietitian-should-i-eat-back-my-exercise-calories/
Thanks -- the advice is actually a bit more nuanced than "don't eat them back."0 -
Unfortunately, the numbers in the energy equation, CICO, never work out in practice like they do on paper. There are several reasons. First the number we use for calories burned a day is an estimate. Even with fitness tracking software, it's an estimate. Our calories consumed per day is another estimate. Depending on how accurate you track (do you weigh everything you eat on a scale? If you don't you should! Measuring cups DON'T count! They are for liquids only) that count can be anywhere from a little off, to nowhere even in the ballpark. Add to that water fluctuations, the weight of undigested food in the stomach, and about a million other factors and whatever rate of loss you came up with on paper is thrown completely out the window. Fortunately, even though we can never track it exactly, the energy equation is quite real! What we do know is, that if over the course of several weeks you are not losing weight, you are eating too much. Day to day and even weekly fluctuations in weight are meaningless. You should weigh daily, take an average of the daily weights after a week, then after a month plot those averages. There should be a downward trend. If not, your calorie goal is either too high, or you aren't tracking accurately and need to work on that.The glycogen/salt thing makes sense. Like I said, not that I'm complaining, I'm just a numbers/science type of gal so I wondered how it worked.
The reason people lose more in the beginning is that they usually have full glycogen stores and more margin of error for inaccurate tracking. As you lose weight, glycogen depletes, and the amount of error you can tolerate with your count goes down. When you are close to goal, your margin of error is quite low. This is why some people struggle greatly with the "last few lbs".
Listen to this
This is wise and great advice.0
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