Excessive calorie decifit?

kittynurse

Hello there. I'm wondering if anyone has an (informed) opinion about exactly how much of a daily caloric deficit is too much. Is there some point at which, even if you are eating a reasonable number of calories, your caloric expenditure is high enough to necessitate an increase in calorie consuption in order to more effectively actually lose fat? For example, if you're on a 1500 cal/day diet and you burn 3000 calories a day, is there any real risk of slowing your fat loss due to the high caloric deficit? Thanks in advance for sharing your insights!

amymeenieminymo

If I am understanding your question right, eating 1500 per day and burning 3000 calories would put you at -1500 calories a day.....so you wouldn't be getting any calories (fuel) for your body and you would be 1500 in the hole. I don't think a person could even survive very long doing that. My apologies if I did not understand the question.

kittynurse

Theoretically, weight loss is a simple mathematical equation: calories out - calories in = calorie deficit. A 3500 calorie deficit = a weight loss of 1 pound. Most weight loss resources suggest aiming for a 500 calorie per day deficit so that you lose 1 pound each week (500 calories per day x 7 days = 3500 calories). The example I gave in my first post was merely hypothetical; I could have just as easily asked about a person eating 2000 calories per day and burning 3000 calories per day. The question is whether or not there is a point at which that deficit is great enough that it actually hinders fat loss, ie if you are taking in 1000 or 1500 or 97million calories fewer than you burn each day, do you actually impede fat loss?

Look at the people on the Biggest Loser. The trainers state that most of the participants are on 1200-1500 calorie per day diets, and their caloric output is targeted at 6000-8000 calories per day (which obviously sounds insane, but I'm just reporting what Bob said on the show); they seem to lose cartloads of weight every week. It seems like there would be a point at which the caloric deficit was so high that the body would stop functioning efficiently enough to continue to lose fat. Does anyone know if this is acutally the case?

Jovialation

i think you may be understanding the numbers given to you here wrong. the calories you burn a day that are used to determined what you should eat do not count as exercise calories

kittynurse

No, I mean in general, your total caloric expenditure over the course of a day (which is obviously influenced by activity); I'm not referring to the math on the site or the calculations they use.

EKarma

Yeah.. but they have enough fat that their bodies can live off of for a while. They also keep doctors on the set.. They are all very watched after.. I wouldn't recommend doing something like that unless you've got a personal trainer and a dietican on hand. My personal opinion.. But those guys do make me jealous.. losing 10 lbs in a week.. Where do I sign up!? :noway:

stormieweather

You really need some calories just to exist. Your organs require calories/fuel in order to function.

"Theoretically" speaking, you could stop eating completely and let your body use fat instead of food as fuel until you ran out. But the damage you would do to your metabolism, your muscles and your well being would be enormous. In addition, the first time you actually put a single calorie in your stomach, your starving body would instantly store it as fat out of pure desperation. You would never be able to eat normally again without putting all that weight back on.

Thus, the MFP plan which gives you a minimum daily intake and a healthy deficit of 500 or 1000 calories a day. This way, your body is getting adequate fuel and you are eating normally, just slightly less than usual.

The people on BL are under medical supervision. It is a tv show designed to keep people's interest for X weeks, not institute a long term lifestyle change.

Azdak

Theoretically, weight loss is a simple mathematical equation: calories out - calories in = calorie deficit. A 3500 calorie deficit = a weight loss of 1 pound. Most weight loss resources suggest aiming for a 500 calorie per day deficit so that you lose 1 pound each week (500 calories per day x 7 days = 3500 calories). The example I gave in my first post was merely hypothetical; I could have just as easily asked about a person eating 2000 calories per day and burning 3000 calories per day. The question is whether or not there is a point at which that deficit is great enough that it actually hinders fat loss, ie if you are taking in 1000 or 1500 or 97million calories fewer than you burn each day, do you actually impede fat loss?

Look at the people on the Biggest Loser. The trainers state that most of the participants are on 1200-1500 calorie per day diets, and their caloric output is targeted at 6000-8000 calories per day (which obviously sounds insane, but I'm just reporting what Bob said on the show); they seem to lose cartloads of weight every week. It seems like there would be a point at which the caloric deficit was so high that the body would stop functioning efficiently enough to continue to lose fat. Does anyone know if this is acutally the case?

The issue is not clear cut, due to the tremendous variation in individuals and how they respond. The general guidelines are that you shouldn't go above a 1000 Kcal/day deficit or below around 1,200 Kcal/day intake (this is the average person trying to lose weight on their own--a medically supervised program might be different).

The general sense from research I have read is that anyone on a restricted calorie diet (within the guidelines stated above) is going to lose some fat free mass (FFM) in addition to fat loss--some studies have reported up to 50% of total weight lost is FFM. The inclusion of exercise and strength training mitigated the loss of FFM compared to non-exercisers (in some cases by 50%), but they still lost FFM. From what I read, if you were going to go on a 2-3 lb/wk wt loss program, you are going to lose FFM, no matter what. It's a question that getting off the weight is more important short term than trying to conserve 100% of FFM. Reshaping your body composition comes a little farther down the road. That was certainly my experience when I lost 30 lbs in my first 2 months. Unfortunately, I did not take a thigh circumference when I started, but I noticed that my legs really decreased in size. I also really struggled to increase my weights when strength training. As I shifted to a less-aggressive calorie deficit, I started seeing steady increases and some notable increases in muscle mass (e.g. chest circumference).

The other research I saw suggested that resting metabolism also decreased with a reduced-calorie diet. This was also offset somewhat with exercise, but not completely. The interesting thing was that the change was not permanent--it reversed itself once subjects resumed a maintenance eating program. The study seemed to indicate that the concern of "permanent starvation mode" occurring as a byproduct of long-term very low calorie dieting was unfounded.

Again, these studies usually can only look at one small part of the big product, and it is a complex picture. So I would expect that others may have seen other research that may add some nuances or even suggest some different conclusions.

The way I look at it is that each individual has different needs, different goals, and different reasons for losing weight. For many people, there are several different stages to the process: Stage 1 is the need to see some fairly quick results, for both health reasons and as positive reinforcement. During this stage, losing some FFM or even slowing down metabolism a little is of secondary importance (but exercise is still crucial); Stage 2 is the "plateau" period, when results have slowed, but significant weight loss has occurred and now the person has the fitness level and the skills where they can ramp up their exercise program, be more aggressive with both cardio and strength and start reshaping your body; Stage 3 is the maintenance phase where the focus is on implementing behaviors that become part of a permanent lifestyle change and ensure that the weight loss is permanent.

It's not a fixed sequence--this is a general picture and I think many of us work on stages 2 and 3 simultaneously, but it is a general approach. Losing 10% of your body weight can have significant health benefits--much more significant than losing the last 10%. For those who are obese or have some acute health concerns, losing the initial weight fairly quickly is very significant--even if there are some negative side effects (i.e. loss of FFM). OTOH, 95% of "diets" fail within 2 years. Which is why one should be *extremely* wary of ANY short-term "success" claims. Personal anecdotes that trying a new supplement, or diet, or "cleanse" has resulted in significant weight loss in 2 wks or even 2 months time are useless in evaluating the effectiveness of the intervention.

One of the biggest criticisms of The Biggest Loser is that the weight loss results they show are unrealistic and set exaggerated and irresponsible expectations in the minds of viewers at home. I watched the show for the first time last week, and did some reading afterwards. From what I understand, despite the claim of "medical supervision", participants are free to engage in any extreme behavior they want to maximize their scale losses. In an interview, the first winner of TBL (can't remember his name) said that in the 2 weeks before his final weigh in, he ate almost no solid food, underwent numerous "cleanses", and finally resorted to the old-school wrestler practice of exercising in a rubber suit. He claimed that, by the end, he was so dehydrated he was urinating blood. He also stated that in the 2 weeks after the show ended he gained back almost 40 pounds as his body rehydrated itself and reestablished a more normal physiology. Other participants reported similar practices, although not to that extreme.

July24Lioness

Theoretically, weight loss is a simple mathematical equation: calories out - calories in = calorie deficit. A 3500 calorie deficit = a weight loss of 1 pound. Most weight loss resources suggest aiming for a 500 calorie per day deficit so that you lose 1 pound each week (500 calories per day x 7 days = 3500 calories). The example I gave in my first post was merely hypothetical; I could have just as easily asked about a person eating 2000 calories per day and burning 3000 calories per day. The question is whether or not there is a point at which that deficit is great enough that it actually hinders fat loss, ie if you are taking in 1000 or 1500 or 97million calories fewer than you burn each day, do you actually impede fat loss?

Look at the people on the Biggest Loser. The trainers state that most of the participants are on 1200-1500 calorie per day diets, and their caloric output is targeted at 6000-8000 calories per day (which obviously sounds insane, but I'm just reporting what Bob said on the show); they seem to lose cartloads of weight every week. It seems like there would be a point at which the caloric deficit was so high that the body would stop functioning efficiently enough to continue to lose fat. Does anyone know if this is acutally the case?

Do you need to lose the same type of weight that the contestants on the Biggest Loser need to lose?

That approach works better on the morbidly obese than it does on someone that is merely overweight.

kittynurse

Azdak, thank you SO much for your insights! That is EXACTLY what I was looking for!