Why is losing weight too fast a bad thing?
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bemyyfriend0918
Posts: 241 Member
Just like the title says, my question is, why is losing weight too fast a bad thing?
Obviously, I do not mean eating a dangerously low amount of calories - I know why that's unhealthy.
But let's say someone is really active. They're eating 1800 calories a day but still losing 3lbs a week. They're eating a decent amount of calories...getting necessary nutrients. Is it still not advisable to lose the 3lbs a week? Should they really look into eating more calories to slow the weight loss?
Obviously, I do not mean eating a dangerously low amount of calories - I know why that's unhealthy.
But let's say someone is really active. They're eating 1800 calories a day but still losing 3lbs a week. They're eating a decent amount of calories...getting necessary nutrients. Is it still not advisable to lose the 3lbs a week? Should they really look into eating more calories to slow the weight loss?
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Fast weight loss is typically not sustainable weight loss.
There's no one size fits all answer to your question. We are all unique and so our bodies will react uniquely to weight loss.2 -
If you're active enough, 1800 calories is dangerously low. If you eat 1800 and burn 1800 with exercise (maybe you hiked all day) that leaves zero for everything else.21
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Burning fat is a process - like burning wood, you don't just light it on fire and the whole pile goes poof! Your body can only burn so much fat at once.
If your body needs more energy right now than it can get from burning fat right now, it has two choices - either get energy from somewhere else (by going after muscle tissue) or don't do something it needs to do (like repair damaged cells, efficiently digest food, grow hair). If you ask it to make that decision consistently, it will start to try to get you to lower your activity to save calories with fatigue, weakness, and accelerated appetite & cravings. That combo is often what causes those who lose weight aggressively to gain it back aggressively.
Often people who are early in the process will be losing weight fast and feeling great. The problem is that often feelings of accomplishment and euphoria are simply drowning out the subtle warning signs that you are stressing your body. And often, you feel fine until you hit the proverbial wall and it can take months for energy levels and body processes to recover.45 -
The very fact that someone is losing weight 'too fast' indicates that they're eating in a dangerously large deficit so one of the criteria you've mentioned is out of whack. That they're losing 'too fast' is an indication that their calorie intake, regardless of how large it is, isn't sufficient to meet the minimum requirements they need to maintain healthy body functions.
Calorie intake is relative to that individual. What might be sufficient or even excess calories for one person may be dangerously low for another so you can't just pick an arbitrary number and decide that this is a safe minimum for anyone. A 440lbs man would be woefully malnourished on 1800cals (and they'd be losing weight too fast), whereas a 120lbs woman wouldn't. For the man 1800cal isn't a 'decent' amount of calories or nor would they likely be getting necessary nutrients and this would be clear by the fact that their rate of loss is 'too fast'11 -
The very fact that someone is losing weight 'too fast' indicates that they're eating in a dangerously large deficit so one of the criteria you've mentioned is out of whack. That they're losing 'too fast' is an indication that their calorie intake, regardless of how large it is, isn't sufficient to meet the minimum requirements they need to maintain healthy body functions.
Calorie intake is relative to that individual. What might be sufficient or even excess calories for one person may be dangerously low for another so you can't just pick an arbitrary number and decide that this is a safe minimum for anyone. A 440lbs man would be woefully malnourished on 1800cals (and they'd be losing weight too fast), whereas a 120lbs woman wouldn't. For the man 1800cal isn't a 'decent' amount of calories or nor would they likely be getting necessary nutrients and this would be clear by the fact that their rate of loss is 'too fast'
Exactly what does a 440lb man need to “nourish” that can’t be done in 1800 calories?
There is no research that I am aware of that suggests that losing weight “too fast” (which you haven’t defined) is unhealthy for someone that large. Quite the contrary.
I think you can make a general argument against losing weight “too fast”, but I don’t think you have picked the best example to make that argument.
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bemyyfriend0918 wrote: »Just like the title says, my question is, why is losing weight too fast a bad thing?
Obviously, I do not mean eating a dangerously low amount of calories - I know why that's unhealthy.
But let's say someone is really active. They're eating 1800 calories a day but still losing 3lbs a week. They're eating a decent amount of calories...getting necessary nutrients. Is it still not advisable to lose the 3lbs a week? Should they really look into eating more calories to slow the weight loss?
If someone is large enough and active enough that they can eat a healthy amount of calories (and I would certainly put 1800 into the “healthy” category), and, with activity they are expending enough to lose 3 lbs per week, then, no that is not unhealthy, nor is it “too fast”. However, seeing as you have to be pretty fit and pretty fat to incur that deficit, not many are going to qualify.
For the most part, however, this is going to be a self regulating process. The longer you go with a plan like this, the less likely you are to be able to sustain it.
As you lose more weight, your TDEE will also become lower, meaning it will be more difficult to sustain that high a deficit while still eating a healthy amount of food. And if you are sustaining a large enough volume of exercise to create that deficit, you will likely start to struggle to maintain that effort without enough fuel.
So, in theory, yes it is possible to lose weight at a higher rate and be healthy. The “1-2 lb per week” recommendation is good for most people, but it is not sacrosanct. Practically, it is difficult to sustain for very long.
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I was using extreme examples to illustrate the point that different people have different caloric needs and that an arbitrary number, no matter how high it seems constitutes a 'safe for everyone' level. A point that holds true regardless and a point you seem to concede in your last paragraph.
Someone consuming 1800 cals per day and losing at 3lbs per week has a maintenance of 3300cal/day either from body size or from activity. Either way their body size or their activity will be burning off a lion share of those 1800 calories which leave insufficient energy left to maintain bodily functions.
This doesn't even touch on how unsustainable a severe calorie deficit like that would be to maintain.12 -
Rapid weight loss can have a lot of negative side effects, even if you are I taking proper nutrients. This includes muscle loss, hair loss, loss of menstrual cycle, and kidney stones, among other potential side effects. Not to mention that maintaining large deficits if likely to lead to fatigue and an increased desire to binge as eventually your body is going to fight back.9
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Two people are disagreeing with all the good advice in this thread. 🤪8
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Maybe the question can be recut. Is losing 1kg a week automatically bad/too fast or can it be safe/healthy even if you are not extremely obese?0
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The body can not burn (or gain) an infinite amount of fat per day.
Medically-prescribed VLCDs (Very Low Calorie Diets) are used for fast weight loss, but only in the case of imminent fatal health emergencies.
VLCDs are only prescribed for short term periods, and they always are followed by normal-eating diet breaks.
There is far too much science about metabolism (and the many interacting chemical/hormonal/internal/external influences that affect our eating and weight loss) to write a summary in a post and get it perfect.
Losing weight "too fast" can help medically and emotionally BUT ONLY FOR SHORT PERIODS of a month or so.
Otherwise, it is "a bad thing".
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NorthCascades wrote: »If you're active enough, 1800 calories is dangerously low. If you eat 1800 and burn 1800 with exercise (maybe you hiked all day) that leaves zero for everything else.
The 2 people who disagreed with this are probably really worried about their own behaviour.
It's hard when you first start looking into MFP and/or dieting, and you've seen the old stories and advertisements elsewhere about people losing weight quickly by being really "motivated" etc.
If I could name the biggest problem I've seen for people quitting/"failing"/struggling, and yo-yo dieting, it's people thinking they shouldn't eat back exercise calories.17 -
koalathebear wrote: »Maybe the question can be recut. Is losing 1kg a week automatically bad/too fast or can it be safe/healthy even if you are not extremely obese?
1 kg a day (2.2 lb) is not automatically bad. Losing about 1% of body weight per week is recommended. Can it be safe/healthy if you are 5'3, 135, losing vanity weight? IMO, no. That's because of math.
Someone 35, lightly active, with those stats probably burns about 1800 per day. There's no way to cut enough to sustain a loss of 2.2 lb without it being too low.
Yes, the person can add exercise -- say running on average 10 miles a day -- to add another 1000 cals a day, but obviously with that amount of intense exercise they will need more cals to avoid over-taxing their bodies.
I tend to think this is more the situation being considered, and not the 440 lb man (who certainly can lose faster).
It's not just a matter of nutrition, if you lose too fast in this case you will lose more muscle and can have negative effects on sleep, hair and nails, as well as the other things mentioned, and will likely end up with all the symptoms of overtraining, as well as potential hormone disruption, at minimum.3 -
What Are the Risks of Rapid Weight Loss?
Rapid weight loss creates physical demands on the body. Possible serious risks include:- Gallstones, which occur in 12% to 25% of people losing large amounts of weight over several months
- Dehydration, which can be avoided by drinking plenty of fluids
- Malnutrition, usually from not eating enough protein for weeks at a time
- Electrolyte imbalances, which rarely can be life threatening
Other side effects of rapid weight loss include:- Headaches
- Irritability
- Fatigue
- Dizziness
- Constipation
- Menstrual irregularities
- Hair loss
- Muscle loss
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When you are in a caloric deficit - your body finds the needed energy elsewhere. Aiming for a slow & steady weight loss while also eating plenty of protein and doing weight training means your body will take the majority of what it needs from your fat stores, and very little from muscle. Going too fast means your body will take more from muscle. Losing muscle has negative consequences.2
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What Azdak said.
All you people disagreeing with him have been drinking the MFP Kool Aid.
Someone who is morbidly obese would do fine on 1800. It is way more important to get that weight off as soon as possible (for the obese/morbidly obese.)
That person has plenty of body fat to use as fuel. It's important to get good nutrition with that 1800, but it would be more than sufficient - regardless of activity level.11 -
I was happy to see one of your answers was that not everyone is the same for what is too low. I lost a little over 90 pounds in a little over one year. I was not getting in enough iron somehow and ended up in the hospital for four days getting blood transfusions and transfusions of iron and a work up to see what was causing the such a low iron and hemoglobin. they looked for bleeding and cancer and couldn't find anything, so the only thing was my diet and quick weight loss as possible cause. someone said to me, 91 pounds isn't that fast of a weight loss in one year. It was for me.
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cmriverside wrote: »What Azdak said.
All you people disagreeing with him have been drinking the MFP Kool Aid.
Someone who is morbidly obese would do fine on 1800. It is way more important to get that weight off as soon as possible (for the obese/morbidly obese.)
That person has plenty of body fat to use as fuel. It's important to get good nutrition with that 1800, but it would be more than sufficient - regardless of activity level.
I didn't disagree with Azdak. But it's possible that people are looking at OP's picture, considering the possibility that she is asking about herself, and automatically disagreeing with anything that might seem to give her permission. I'm not saying that's a good reason, mind you
just thinking out loud. 6 -
Thinking of the body as a biological system - these systems adapt well under gradual changes - much better than under dramatic changes. Drastic changes result in stress - some quantifiable, some not. This is why very low calorie diets/low calorie diets require some manner of medical monitoring.
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cmriverside wrote: »What Azdak said.
All you people disagreeing with him have been drinking the MFP Kool Aid.
Someone who is morbidly obese would do fine on 1800. It is way more important to get that weight off as soon as possible (for the obese/morbidly obese.)
That person has plenty of body fat to use as fuel. It's important to get good nutrition with that 1800, but it would be more than sufficient - regardless of activity level.
I didn't disagree with Azdak. But it's possible that people are looking at OP's picture, considering the possibility that she is asking about herself, and automatically disagreeing with anything that might seem to give her permission. I'm not saying that's a good reason, mind you just thinking out loud.
Of course. That's when reading is helpful.
..and then, sometimes I don't read either.
I just think Azdak has been one of the most helpful and knowledgeable posters on MFP for many years. I tend to White Knight those people.4
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