What's the maximum deficit needed to avoid 'starvation mode'

Dom_m

My BMR+daily activity is about 2,340 calories, hence my MFP target is 1,340 (I'm impatient and I know I wont quite, which seems to be the main reason given for gradualism).

All of last week I had net calories between 700-1400, mostly closer to 700. Obviously, as an 84kg (185pounds) male, just under 30years, 183cm (6"1'), this is still low. The trouble is that my exercise calories are such wild estimates. I typically spend 10-15 hours at the gym per week. For intense exercise I estimate 600 calories per hour. For less intense I estimate 250 (taigalates) or 500 for moderate intensity. The trouble is, each of these estimates have a +/- range of about 150 calories / hour, so I really need a calorie range, not a simple target.

I guess net calories of anything less than 1,800 is still good progress (though I only ever manage that much when I binge drink), but what should I consider my absolute minimum net calories? If I get 700 net, that's a 1,640 deficit - is that too few? What's the maximum deficit I need to stay out of 'starvation mode'? 840 net calories would be 1,500 deficit - should I set my range as 840-1800 calories per day, aiming for the middle, but never leaving the range, or is this range too wide?

Cheers.

FiitChiik

What are your goals? How much are you trying to lose? If you would like to track you calories more accurately, it would be a good idea to invest in a heart rate monitor. They are great at keeping track of how many calories you burn whether you are doing cardio or weight lifting.
Also, to get a better estimate of your BMR* you should find out what your body fat % is. Your caloric intake for the day should not be below your BMR for healthy and long lasting weight loss! Knowing how much lean mass you have is a valuable tool, just make sure you use a reliable and accurate method of testing (if your really serious hydrostatic weighing is the best).

*Rember: your BMR is the amount of calories you body burns a day just staying alive!

FiitChiik

What are your goals? How much are you trying to lose? If you would like to track you calories more accurately, it would be a good idea to invest in a heart rate monitor. They are great at keeping track of how many calories you burn whether you are doing cardio or weight lifting.
Also, to get a better estimate of your BMR* you should find out what your body fat % is. Your caloric intake for the day should not be below your BMR for healthy and long lasting weight loss! Knowing how much lean mass you have is a valuable tool, just make sure you use a reliable and accurate method of testing (if your really serious hydrostatic weighing is the best).

*Rember: your BMR is the amount of calories you body burns a day just staying alive!

SHBoss1673

Well, the general "rule of thumb" for guys is similar to that 1200 number for ladies but it's 1800 for men. That being said, that's probably the most generic (and slightly embarrassing) thing I've ever said.

all that said, it really does depend on you.

even if the calorie estimates are wildly inaccurate, being at 700 calories for a guy is going to be an issue. IMHO you should buy yourself an HRM, while they aren't 100% accurate (closer to 90% accurate), they WILL allow you to be relatively sure about your caloric expendature.

Depending on where you are health wise (are you obese, morbidly obese, overweight, high body fat %, low muscle mass...etc) you can taylor your calorie expendature to fit your needs, but I'll tell you this, as a guy who is 6 foot 2 inches (163 cm) and was once (3 years ago, when I started on MFP) 235 lbs, you should probably never go below about 1400 calories even taking exercise into account, and only if you are well into the obese category or have a body fat % in the 20's or higher, any lower that that and you're probably doing as much bad as you are good.

Dom_m

Cheers. I guess I have to start eating more calorie dense foods - I don't think I could possibly eat more grams of food! I already spend most of the day eating (I'm vegan and on a macrobiotic diet, eating mostly vegetables, so getting calories takes a fair bit of eating).

In terms of where I am health wise, my bmi is 24.4,
According to: http://www.healthcentral.com/cholesterol/home-body-fat-test-2774-143.html
I have 15.5% body fat (13 Kilograms of fat and 71 Kilograms of lean - muscle, bone, body water)

Basically your photo is pretty similar to my build.

I suppose I need to change my targets in MFP. I've been overweight my whole life and was 110kg (242 pounds) when I was 18, so the idea of deliberately eating more is hard to come to grips with, especially when I feel like I already spend the whole day eating!

SHBoss1673

yeah, there's no way you should be anywhere near 700 calories a day, my recommendation, with your numbers, would be a VERY small deficit (I'd say a 250 calorie deficit, INCLUDING EXERCISE), as your body doesn't have much body fat to play with and trying to lose to much will just screw up your metabolism and frustrate you.

Dom_m

Cheers. I think I'll work up to it a few hundred calories at a time. I think if I aim for 1400-1500 this week, I can get 1800 next week. That way I can keep measuring myself and check if my body's ready to use the extra energy.

This is the weirdest eating plan I've ever been on. Its like non stop eating! And I think I'll have to exercise less or my food bill will make me broke! Bizarre.

Dom_m

Found a couple of articles that address my question directly. They are both based on the same paper published in the Journal of Theoretical Bioligy (March, 2005).

Source: http://baye.com/calculating-the-daily-calorie-deficit-for-maximum-fat-loss/


From the article:
“A limit on the maximum energy transfer rate from the human fat store in hypophagia is deduced from experimental data of underfed subjects maintaining moderate activity levels and is found to have a value of (290 ± 25) kJ/kg d. A dietary restriction which exceeds the limited capability of the fat store to compensate for the energy deficiency results in an immediate decrease in the fat free mass (FFM). In cases of a less severe dietary deficiency, the FFM will not be depleted.”

290 kilojoules = 69.31 kilocalories and 1 kilogram = 2.2 pounds, so 290 kJ/kg = 31.4 kcals/lb

Simply stated, the maximal daily calorie deficit for fat loss is approximately 31.4 cals per pound of fat, give or take about 3 calories, and if your daily calorie deficit exceeds this the difference is going to come from other tissues, including your hard-earned muscle.

In my case, with about 28 pounds of fat, this paper suggests I can maintain a caloric deficit of 28 x 31.4 = 880 per day and continue to have all the energy come from fat cells and not from lean tissue mas. Increasing my deficit further would simply result in loss of mussel, but maintaining a smaller deficit would lead to slower fat loss. This is about 6,160 calories per week which is close to 2 pounds / week.

In addition to this, the paper suggests that highly active lifestyles (ie: lots of exercise) are likely to increase the maximal energy use from fat. This is really important, but is only a hypothesis, not a finding, of the paper. It would imply that a deficit derived from exercise can be larger than a deficit derived from eating less, and still result in 100% deficit being filled by fat loss.

I wonder what people think of this.

SHBoss1673

Dom_m, this jibes directly with what I've always said.

Which is, the more fat you have to lose, the faster you will be able to lose it.

Couple of things to point out though that were mentioned in the link and are important.

- Mr Baye correctly points out that while these numbers are most likely highly accurate, people should take into account hormonal and thermic changes in the body which will make total fat burned less than the optimal amount predicted.
Specifically this refers to the human famine response AKA "Starvation Mode". Assuming your body will burn the maximum
amount every day is a recipe for failure. Which is why I preach moderation, tweaking, and giving your body time to adjust to
new caloric requirements.

- Certain segments of the population should NOT prescribe to this formula, specifically those over the age of about 55, and pregnant women, as well as people with metabolic syndrome, diabetes, other hormone regulation issues, and those who have a physical impairment. Also to note are people with food allergies which can severely impact how your body processes carbohydrates, and creates glycogen and removes sugar from the blood.

-As you approach optimal weight and body fat % this formula tends to break down a little as, what little fat you DO have left is usually stored in places that are relatively far from blood supply, therefore more difficult to use metabolically. When people ask questions like "How come I'm losing fat everywhere but the place I want too?" This is the answer to that question 9 times out of 10. Fat is metabolized based on it's proximity to the blood supply, fat can't be mobilized if it's not close enough to blood to be transported, therefore, "old" fat cells that have been compressed and "shoved" away from the blood are far more difficult to remove, and will take a little extra persistence.

These are just things that I thought people should be aware of, I think that's a great little article Dom_m, although it might go over a lot of people's heads with the numbers, it's a good piece.

gurlondrums

I was just browsing and came across this.

Banks, what you said about the "why am I losing fat everywhere but where I want to" question really helps. I did my measurements yesterday and lost MAJOR inches off my arms (they're all toned now, I love it) and my legs, but almost no difference around my waist. So I'll have to keep that in mind. Thank you much for your wisdom. :drinker:

Dom_m

Yep, agree with all you said and the possibility that old fat would be pushed away from the blood stream is eye opening. Thanks.

I realised the source of my impatience today. In an effort to avoid measurement error effects, such as inconsistent measuring technique, water loss etc I've been taking wight, neck, waste, chest, thigh and bicep measurements every morning. The reason to do it each day instead of weekly is that the occasional wild fluctuation gets ironed out when its surrounded by a bunch of consistent measurements, but if the wild fluctuation happens to occur on a weekly measurement day, it seems more 'real' and therefore misleading.

The problem is of course, I'm paying way too much attention to progress! I just looked back, and I only started with MFP on 15 January (3 weeks and 2 days). So my progress is actually really good even though it seems slow as hell. I think I'll keep the daily measurements at least until the end of the month, but I might switch to weekly after that, just to stop messing with my psych

SHBoss1673

Yep, agree with all you said and the possibility that old fat would be pushed away from the blood stream is eye opening. Thanks.

I realised the source of my impatience today. In an effort to avoid measurement error effects, such as inconsistent measuring technique, water loss etc I've been taking wight, neck, waste, chest, thigh and bicep measurements every morning. The reason to do it each day instead of weekly is that the occasional wild fluctuation gets ironed out when its surrounded by a bunch of consistent measurements, but if the wild fluctuation happens to occur on a weekly measurement day, it seems more 'real' and therefore misleading.

The problem is of course, I'm paying way too much attention to progress! I just looked back, and I only started with MFP on 15 January (3 weeks and 2 days). So my progress is actually really good even though it seems slow as hell. I think I'll keep the daily measurements at least until the end of the month, but I might switch to weekly after that, just to stop messing with my psych

yep, that's true, while measurements are a better predictor than weight alone. Really it's recommended to not take too seriously any fluctuations that aren't at steady for at least two weeks. That being said, any 1 week measurement you take can be off, but if over two weeks you have the same measurement then it's more likely to be accurate. It's in this way we need to train ourselves to be patient with the progress. Happens to all of us though, I do the same thing, I get frustrated when I start a new program and don't see immediate results.