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How many calories in body fat

Say for example I burnt 2000 calories in a day but only consumed 1600. My body would then have to burn X grams of body fat to make up the 400 calorie deficit.

How much body fat would have to be burnt to make up 400 calories? or is it different for everyone?
Roughly 3500 calories = 1lb body fat.

That's the same for everyone I think - it's just some people burn more calories.
Reply 2
Original post by blue n white army
Say for example I burnt 2000 calories in a day but only consumed 1600. My body would then have to burn X grams of body fat to make up the 400 calorie deficit.

How much body fat would have to be burnt to make up 400 calories? or is it different for everyone?

The body does not work like that. Nutrients are metabolized differently and stored separately so you need to manage carbohydrate, fat and protein intake separately (i.e. your body might not necessarily make up the 'deficit' from fat stores).

If you want to reduce fat mass then you need to have a negative fat balance. You achieve this by reducing your intake of saturated fats and maximizing the oxidation of fats by exercising for several hours a day. Simply reducing your calorie intake is not an intelligent approach because (1) you need carbohydrates and proteins to oxidise fats and (2) your metabolism may need more than 2000 calories; the extra exercise will only compound your malnutrition.

I would go and see a doctor. They will take various factors into consideration before giving dieting advice. That is more than we on the internet can do.
(edited 10 years ago)
Reply 3
Original post by evantej
I would go and see a doctor. They will take various factors into consideration before giving dieting advice. That is more than we on the internet can do.


definitely do not do this

as for your question, not all of the deficit in calories will come from fat stores. It could come from glycogen in the liver, skeletal muscle, etc. no way to work out exactly how much fat mass is being lost. all you can do is try and minimise muscle loss by keeping protein intake high enough and weight training frequently
Reply 4
Original post by bertstare
definitely do not do this

as for your question, not all of the deficit in calories will come from fat stores. It could come from glycogen in the liver, skeletal muscle, etc. no way to work out exactly how much fat mass is being lost. all you can do is try and minimise muscle loss by keeping protein intake high enough and weight training frequently


Why?
Reply 5
Original post by evantej
Why?


The amount the average doctor knows about fitness and nutrition is terrible
Reply 6
Whose body fat? i doubt its that simple and every case has variable factors
Original post by evantej
Why?

The main reason I think would be wasting a doctor's time and nhs money with trivial bull****
Original post by evantej
The body does not work like that. Nutrients are metabolized differently and stored separately so you need to manage carbohydrate, fat and protein intake separately (i.e. your body might not necessarily make up the 'deficit' from fat stores).

If you want to reduce fat mass then you need to have a negative fat balance. You achieve this by reducing your intake of saturated fats and maximizing the oxidation of fats by exercising for several hours a day. Simply reducing your calorie intake is not an intelligent approach because (1) you need carbohydrates and proteins to oxidise fats and (2) your metabolism may need more than 2000 calories; the extra exercise will only compound your malnutrition.

I would go and see a doctor. They will take various factors into consideration before giving dieting advice. That is more than we on the internet can do.


I'm sorry, but this is the biggest load of rubbish I've seen for a while.

A negative calorie balance will suffice. There is absolute no need to start calculating things in the depth that you suggest - how many people do you think will stick to that? There's no need to remove fat from your diet, there's no need to exercise for 'several hours per day' and, in the most part, there's also absolutely no need to see a doctor! Where did you learn all this??

This isn't necessarily something that I'm proud of, but when I started to lose weight a lot of my calories were made up from fat. If anything I probably had more fat than I had before, replacing healthier foods with fatty ones!! I mean yes, it's not great, but I still lost weight - two stone in fact - before I properly reassessed my diet and started thinking about things from a health POV rather than just a weight loss one.
Reply 9
Original post by xoxAngel_Kxox
I'm sorry, but this is the biggest load of rubbish I've seen for a while.

A negative calorie balance will suffice. There is absolute no need to start calculating things in the depth that you suggest - how many people do you think will stick to that? There's no need to remove fat from your diet, there's no need to exercise for 'several hours per day' and, in the most part, there's also absolutely no need to see a doctor! Where did you learn all this??

This isn't necessarily something that I'm proud of, but when I started to lose weight a lot of my calories were made up from fat. If anything I probably had more fat than I had before, replacing healthier foods with fatty ones!! I mean yes, it's not great, but I still lost weight - two stone in fact - before I properly reassessed my diet and started thinking about things from a health POV rather than just a weight loss one.


You are putting words in my mouth/deliberately misreading. I said if they wanted to lose weight they have to reduce (not remove) the amount of fat they consume and exercise. I never said they had to calculate anything in depth (in some cases you cannot calculate things anyway). I simply highlighted that reducing calories is not the best approach because you need an adequate supply of carbohydrates and proteins to aid weight loss and build muscle. Do you want me to provide you with biochemistry and medical resources which prove this?

I suggested going to see a doctor to get advice about effective weight loss. There is nothing wrong with that. (I take bertstare's scepticism with a pinch of salt). You clearly have a perverse view about what doctors are for (i.e. only see them when you are 'sick'). But then you did not actually provide any advice... you just told us how fat you used to be and how you now think about things from a health perspective rather than just a weight loss one... :rolleyes:
Original post by evantej
You are putting words in my mouth/deliberately misreading. I said if they wanted to lose weight they have to reduce (not remove) the amount of fat they consume and exercise. I never said they had to calculate anything in depth (in some cases you cannot calculate things anyway). I simply highlighted that reducing calories is not the best approach because you need an adequate supply of carbohydrates and proteins to aid weight loss and build muscle. Do you want me to provide you with biochemistry and medical resources which prove this?

I suggested going to see a doctor to get advice about effective weight loss. There is nothing wrong with that. (I take bertstare's scepticism with a pinch of salt). You clearly have a perverse view about what doctors are for (i.e. only see them when you are 'sick'). But then you did not actually provide any advice... you just told us how fat you used to be and how you now think about things from a health perspective rather than just a weight loss one... :rolleyes:


It's not just reducing fat though!

And I didn't say how fat I used to be. Only that I'd lost weight. At no point did I mention how fat I was. All I said was that you can lose weight without cutting fat - which you can.

Reducing calories is by far the most effective method of weight loss and the only one that will work long term.
Original post by evantej
You are putting words in my mouth/deliberately misreading. I said if they wanted to lose weight they have to reduce (not remove) the amount of fat they consume and exercise. I never said they had to calculate anything in depth (in some cases you cannot calculate things anyway). I simply highlighted that reducing calories is not the best approach because you need an adequate supply of carbohydrates and proteins to aid weight loss and build muscle. Do you want me to provide you with biochemistry and medical resources which prove this?


You don't need to reduce dietary fat, you could eat 100% fat and still lose weight (not that it would be the best idea). You don't need carbohydrates, they aren't vital, dietary fat is. You can function perfectly fine on zero(or close to zero) carbohydrate diets, keto for example.
Original post by evantej
You are putting words in my mouth/deliberately misreading. I said if they wanted to lose weight they have to reduce (not remove) the amount of fat they consume and exercise. I never said they had to calculate anything in depth (in some cases you cannot calculate things anyway). I simply highlighted that reducing calories is not the best approach because you need an adequate supply of carbohydrates and proteins to aid weight loss and build muscle. Do you want me to provide you with biochemistry and medical resources which prove this?

I suggested going to see a doctor to get advice about effective weight loss. There is nothing wrong with that. (I take bertstare's scepticism with a pinch of salt). You clearly have a perverse view about what doctors are for (i.e. only see them when you are 'sick'). But then you did not actually provide any advice... you just told us how fat you used to be and how you now think about things from a health perspective rather than just a weight loss one... :rolleyes:


What Scoobiedoobiedo said above. If you aren't in negative energy balance, you aren't going to lose weight. I find it quite perplexing that you believe exercising on a caloric deficit would "compound your malnutrition".
It'd be incredibly difficult to eat at a mild caloric deficit and not get adequate carbohydrate and protein. Do you think people would just be ingesting solely pure olive oil if we told them to forget about macro management?
Reply 13
Original post by Hype en Ecosse
What Scoobiedoobiedo said above. If you aren't in negative energy balance, you aren't going to lose weight. I find it quite perplexing that you believe exercising on a caloric deficit would "compound your malnutrition".
It'd be incredibly difficult to eat at a mild caloric deficit and not get adequate carbohydrate and protein. Do you think people would just be ingesting solely pure olive oil if we told them to forget about macro management?

You are missing my point. Unless they have an incredibly unhealthy diet now the OP will have a negative energy balance simply by doing more exercise (i.e. they could lose weight with no changes to their diet at all).

They are clearly looking to lose weight more quickly by reducing their intake as well. The point I was making about this is that looking purely at reducing calories across the board is not the smartest idea because the body will crave more energy because of increased exercise levels. If they are looking to lose fat - which they are, look at their comment - then it makes sense to start reducing their intake of fat before they cut other things out. That way they are less likely to lose muscle with increased exercise, and far more likely to keep at it and be successful.
Original post by evantej
You are missing my point. Unless they have an incredibly unhealthy diet now the OP will have a negative energy balance simply by doing more exercise (i.e. they could lose weight with no changes to their diet at all).


You'd be surprised. Exercise-only interventions that make no effort to adjust dietary habits show extremely poor weight loss outcomes. I've just did a quick literature search for some systematic reviews on the topic (since you're not likely going to believe me that it's true just because I say "that's what I've been taught." :tongue:):
Cochrane managed to find 2 trials of 54 women that recorded data on exercise and postpartum weight loss in women, it showed no significant benefit over "usual care". Whereas diet and exercise was in 7 trials and n = 573.
http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD005627.pub3/full. Same results were found investigating the general population: low intensity exercise-alone ineffective for weight loss (but high intensity alone produced significant change - this relationship only held without dietary change) at 4 trials and n = 317.
http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD003817.pub3/

They are clearly looking to lose weight more quickly by reducing their intake as well. The point I was making about this is that looking purely at reducing calories across the board is not the smartest idea because the body will crave more energy because of increased exercise levels. If they are looking to lose fat - which they are, look at their comment - then it makes sense to start reducing their intake of fat before they cut other things out. That way they are less likely to lose muscle with increased exercise, and far more likely to keep at it and be successful.


This doesn't hold in the realm of clinical practice and the general advice for the population is calorie restriction.

I'm not saying fat restriction isn't a great way to lose weight. Plenty of study designs have investigated the efficacy of FAT-R + exercise regimes - and if someone wants to track their calories and reach a deficit by reducing fat intake, more power to them. But there's no evidence of benefit for doing this over just reducing your calories within ranges of average macronutrient ratios. People's protein intake doesn't tend to plummet when they restrict calorie intake to diet, and the only people who minimise protein catabolism during weight loss are those who purposefully increase protein intake with load-bearing exercise, and people who restrict fat's bodies are going to "crave" just as much energy as people who reduce the equivalent level of calories through broad dietary restriction.
(edited 10 years ago)

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