understanding calorie intake/outake ..?


Full Member
S: 15st8lb C: 15st8lb G: 9st0lb BMI: 35.2 Loss: 0st0lb(0%)
Hi all :)

I have a question about how this diet (and other food replacement diets) work in-respect to the calorie consumption.

So it basically works that you have very little calories (approx 400-500 calories) oer dat, and the amount of calories a woman should have in a day top just maintain is 1500.

And by consuming this small amount of calories, you lose weight.

Ok got all this, but what I don't get is the vast amount we lose/calculations.

If we only have 400 calories a day, that's losing about 1100 calories (a day) x 7 = 7700 calories.

And since 1lb of weight is about 3500 calories, thats only about 2.2lbs

How do we end up losing averages of 3-5lbs a week? By this calculation even if we starved ourselves and ate nothing for 1 week, and did no exercise but just usual walking etc.. we'd only lose 10500calories - which is 3lbs?

How does this make sense?

Am I missing something, or not understanding properly? How does this work?

I really want to know, so I can calculate things - and really understand :( Thanks in advance
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S: 14st1lb C: 8st10lb BMI: 23 Loss: 5st5lb(38.07%)
Hey there

No expert but what springs to mind, when we are bigger we can eat considerably more than 1500 calories to maintain so the deficit is much greater hence as we get nearer to goal the losses slow down.



Silver Member
S: 13st8lb C: 12st4lb G: 11st8lb BMI: 26.1 Loss: 1st4lb(9.47%)
i think on CC you prob loose 2-3lbs of fat a week, and the rest is prob water...

also things like, your body is used to alot more cals, i think its 2000 cals to maintain, activity level all play a part also


Porgeous has it right, someone like me who is 6ft tall and (was) 20stone 5lbs requires in excess of 3650 calories a day to maintain that weight.

So by doing 500 cals a day, I was burning around 3100 calories a day;

times that by 7 = 21700 a week
divide by 3500 = 6.2lbs a week

which is what I lost for the first 4 weeks

at the weigh I am now (17st 2lbs) I need around 2600 to maintain, a little over the 'recommended' for a male adult

burn 2100cals a day * 7 = 14700
divide by 3500 = 4.2lbs of fat a week

now if you have a more active day, series of days, or reach a point where you are physically able to do more, you will burn more calories than stated of course, and so you can still lose more - for instance, I had a very active week last week with work, parties, shopping, walks/runs and so on, so I lost 8lbs, twice as much as the calculations would suggest.

Also, bear in mind that all of the "Calories needed to maintain" I have put in this post are based on the BMR - Base Metabolic Rate, which is what your body needs to lie in bed all day and do nothing but be alive.

So the actual calories needed will be greater than stated, and as such so will the losses.

Hope that clears things up a bit :)


Full Member
S: 15st8lb C: 15st8lb G: 9st0lb BMI: 35.2 Loss: 0st0lb(0%)
Thanks guys, that really makes sense now! Now I must go and do calculations :)

Porgeous - still looking great, and glad your still here :)