Can you have too big a calorie deficit in a day?

[patsfan]

If we all need at least 1200 calories a day, I'm wondering if there's also a maximum calorie deficit per day that's recommended. I journal all of my food and exercise and on some days, I have at least a 3000 calorie deficit once I add my BMR and calories burned at the gym minus the calories I've ingested. If I know there's a max deficit one shouldn't cross, I can alter my caloric intake based on how many calories I've burned at the gym...I just want to keep my metabolism up and sometimes I wonder if I'm not eating enough on gym days.

 

[Steve]

If we all need at least 1200 calories a day,

Where are you pulling that information from?

I'm wondering if there's also a maximum calorie deficit per day that's recommended.

Read this:

 

[Jericho]

I think 3000 a day for an extended time period is too much. You can cause long term health problems if you lose weight too fast. I think the factors you have to look at is how are you responding to it. Your body will tell you more than you think. I would think an extended time of that large of a deficit will cause you to feel tired and hungry..

Actually, listen to Steve

 

[mred]

I've heard that 1000 calorie deficit is the max you should hit. I guess this makes sense because if you should only be losing 2lbs a week max (3500 calories to lose a 1lbs), that comes to 1000/day. I hope that helps =)

 

[patsfan]

Okay the 1200 calorie thing I've read all over the place as an absolute minimum for adults in order to not screw up your metabolism.....but if there are people who can healthily eat less, please tell me!

Thanks for the link, just to clarify what the article said
"Based on a somewhat simplified analysis of what data exists (including the seminal Minnesota semi-starvation experiment), they conclude that the maximal rate at which fat stores can provide energy to the body is 290 +- 25 kj/kg which is approximately 31 kcal/lb of fat per day.

So, if you are carrying a mere 10 lbs. of fat, you can sustain a 310 cal/day deficit.
20 lbs. = 620 calories.
30 lbs. = 930 calories"

According to my BMI and my weight I am carrying 117 lbs of fat, so I mulitply this by 31 and come up with 3627 calories.

Now, can I assume that given my stats at the moment, a 3000 cal deficit per day is just fine, that I could actually burn another 500 cal on top of that for maximum fat loss while sparing lean body mass, as the article states "So, the basic assertion of the paper is that, so long as the net daily deficit does not exceed what your fat stores can provide, you should spare lean body mass."

 

[Jericho]

Just remember to listen to your body as well, sometimes the numbers listed isn't always for you. Do it smart and you will be fine

 

[Tamago]

What exercises are you doing at the gym?

And like Lyle points out in the article the equation still roughly comes out to weight * 10 (at least it did for me) Great article though, even more evidence against extreme dieting..

 

[patsfan]

I'm doing 4-5 days/wk of interval cardio getting up to 85-90% max heart rate on the high end for about 40 minutes. Then resistance training 3x/wk, to include leg press, rotary torso, low row, chest press, back extension, abs, generally all the machines that are not working a single muscle group. This routine was set up for me by a personal trainer. I've been upping my weights every few weeks as I progress, and for my cardio, I'm definitely not doing the slow and steady thing, and I am drenched in sweat after every workout. Oddly, my appetite has been totally curbed and I have to work at getting in 1600 cal/day- most of the time I'm ending the day at between 14-1500. Eating only whole foods- no shakes, etc. 30% protein, 30% fat & 40% carbs.

 

[KaraCooks]

A few clarifications:

Okay the 1200 calorie thing I've read all over the place as an absolute minimum for adults in order to not screw up your metabolism

It's not about screwing up your metabolism prrmarily - it's about nutrition and muscle mass and a whole slew of other things. Once you start dropping into VLCD (very low calorie diets), it's nearly impossible to get all the nutrients you need AND to get enough protein to maintain lean muscle mass w/out some kind of expert/professional guidance. 1200 is a sort of ballpark figure for that - but it depends on the person as well. Medically I believe anything 800 calories and under is considered a VLCD - and as I said, shouldn't be undertaken w/out some kind of professional supervision.

 

[aravind82]

Okay the 1200 calorie thing I've read all over the place as an absolute minimum for adults in order to not screw up your metabolism.....but if there are people who can healthily eat less, please tell me!

Thanks for the link, just to clarify what the article said
"Based on a somewhat simplified analysis of what data exists (including the seminal Minnesota semi-starvation experiment), they conclude that the maximal rate at which fat stores can provide energy to the body is 290 +- 25 kj/kg which is approximately 31 kcal/lb of fat per day.

So, if you are carrying a mere 10 lbs. of fat, you can sustain a 310 cal/day deficit.
20 lbs. = 620 calories.
30 lbs. = 930 calories"

According to my BMI and my weight I am carrying 117 lbs of fat, so I mulitply this by 31 and come up with 3627 calories.

Now, can I assume that given my stats at the moment, a 3000 cal deficit per day is just fine, that I could actually burn another 500 cal on top of that for maximum fat loss while sparing lean body mass, as the article states "So, the basic assertion of the paper is that, so long as the net daily deficit does not exceed what your fat stores can provide, you should spare lean body mass."

As much as others might disagree with you, I tend to have larger deficits as well. I also use the 31 cal/lb of fat number to give myself a "maximum". I've been shooting for a 1500+ calorie deficit (eating 2,000 and burning 3,500-4,000) lately and everything seems fine. Of course this deficit will have to come down as I lose more body fat.

My anecdotal evidence probably isn't worth much but I just wanted to let you know that you're not alone. But judging by your current weight, I'd still recommend eating much more than a measly 1,200 calories. And make sure you're taking the appropriate steps to minimize muscle loss in the process.

 

[Ronbell]

Steve's article kind of tells you that in order to not lose lean mass, you need to basically take your fat mass, multiply it by 31, and that's the maximum amount of calories you can go below maintenance without eating away at your lean body mass. That reduction should be included from the amount of calories burned from exercise.

You should also recalculate as you go along.

ie: 200 pound man, 20% body fat= 40 pounds of fat.

40x31= 1240 calories

Maintenance = body weight x 15 (in articles example, a constant)

.: 200 x15= 3000

Max reduction of maintenance calories lost from diet and exercise is
3000-1240 = 1760

That's my understanding of it anyways.

Which seems around what other people have noticed, the greater the amount of fat, the much larger the deficit you can allow for. In this example, this person would be able to reduce their calories to around the same number i currently consume, even though they are 15 pounds heavier than me.

 

[SydneyTrainer]

I just posted this elsewhere but formulas are always guesses, remember that. Yes some formulas are better than others but the variables are enormous between what each individual needs to eat. Differences in height, muscle mass, exercise, daily activity, metabolism, body type.

Instead the best thing to do is whats called a 24 hour recall. You simply write down EVERYTHING you eat or drink over a 24 hour period. Then enter this into a calorie counting website. This will give you your total calorie consumption/day.

From this point rduce total calories by 500-1000 calories to lose about 1-2 pounds/week. This way you learn about your body, rather than relying on a formula

 

[patsfan]

I just posted this elsewhere but formulas are always guesses, remember that. Yes some formulas are better than others but the variables are enormous between what each individual needs to eat. Differences in height, muscle mass, exercise, daily activity, metabolism, body type.

Instead the best thing to do is whats called a 24 hour recall. You simply write down EVERYTHING you eat or drink over a 24 hour period. Then enter this into a calorie counting website. This will give you your total calorie consumption/day.

From this point rduce total calories by 500-1000 calories to lose about 1-2 pounds/week. This way you learn about your body, rather than relying on a formula

I see what your saying, but your post doesn't mention taking into account your BMR and calories burned through exercise. I do track everything I eat every day on Fit Watch as well as log my gym activity.

 

[Harold14370]

I see what your saying, but your post doesn't mention taking into account your BMR and calories burned through exercise. I do track everything I eat every day on Fit Watch as well as log my gym activity.

I believe that what Sydney Trainer is saying is that if you are not losing weight, then whatever you are eating now, minus whatever you are burning now, is, ipso facto, 500 to 1000 calories too much.