Starvation mode and net calories......

Fat loss results when you provide your body with less total energy in the form of calories than what it uses in a given day when considering every means of energy expenditure (RMR, exercise, non-exercise activity, and food absorption).

For instance, I need to eat 2900 calories just to maintain weight while lifting five days a week. I am reducing fat mass consistently simply because I am eating 2650 calories a day, for a 250 calorie deficit while maintaining my five day lifting program (no increase in activity). One major reason I assume a small deficit is that we all have a limit to how much fat that can be oxidized in 24-hours. Thus, persons with less fat cannot take on the same large deficits as those with far greater fat mass. The closer one gets to their fat oxidation limit, the more weight loss comes from fat-free mass loss.

Thus, fat loss is about ending with less energy than what your body needs to maintain weight relative to activity. With that said, why not lose fat while eating the most amount of calories instead of eating the minimum? I will not go into the topic of starvation mode, but regardless of how significant the deficit, we all experience these alterations: reduced RMR, reduced fat-free mass, reduced leptin, etc. The greater the deficit, and the longer you maintain said deficit, will result in greater changes to the above. With that said, its preferable if one chooses a smaller deficit since it is not so restrictive which makes compliance and returning to maintenance a lot easier and less stressful.

I am not sure but I've heard that a minimum of 1,000 calories is necessary or your body will go into starvation mode and that does not help to lose weight. I would be careful.

Id be interested to hear what your nutritionist says.

From all the stuff I've read, it sounds like you do need to be careful about harming your metabolism. You will lose weight eating so few calories, but you will also gain that weight back quickly because you are slowing down your metabolism by training your body to do as much as it is with less fuel. Check out cutthefatpodcast.com. It has lots of good info for burning fat and keeping it off for the long term.

Fat loss results when you provide your body with less total energy in the form of calories than what it uses in a given day when considering every means of energy expenditure (RMR, exercise, non-exercise activity, and food absorption).

For instance, I need to eat 2900 calories just to maintain weight while lifting five days a week. I am reducing fat mass consistently simply because I am eating 2650 calories a day, for a 250 calorie deficit while maintaining my five day lifting program (no increase in activity). One major reason I assume a small deficit is that we all have a limit to how much fat that can be oxidized in 24-hours. Thus, persons with less fat cannot take on the same large deficits as those with far greater fat mass. The closer one gets to their fat oxidation limit, the more weight loss comes from fat-free mass loss.

Thus, fat loss is about ending with less energy than what your body needs to maintain weight relative to activity. With that said, why not lose fat while eating the most amount of calories instead of eating the minimum? I will not go into the topic of starvation mode, but regardless of how significant the deficit, we all experience these alterations: reduced RMR, reduced fat-free mass, reduced leptin, etc. The greater the deficit, and the longer you maintain said deficit, will result in greater changes to the above. With that said, its preferable if one chooses a smaller deficit since it is not so restrictive which makes compliance and returning to maintenance a lot easier and less stressful.

Thank you. That's such a clear explanation.

You can lose weight very quickly eating about 850 calories/day net. You will also likely reduce your basal metabolic rate so that when you start eating "maintenance", your body actually needs less so it stores more as fat, you regain the weight and then some. But if that's what you like doing... :drinker:

So what everyone is trying to say, is to eat them back? I'm confused. I thought 1300 was a safe amount of calories to eat to lose weight...

But you are not GETTING 1300 .... because you are burning them up.

So what everyone is trying to say, is to eat them back? I'm confused. I thought 1300 was a safe amount of calories to eat to lose weight...

There's no right answer to "safe amount". It depends on a ton of factors: Current weight, exercise levels, activity levels throughout the day, even genetics and metabolism to a certain extent. That said, you are not eating anywhere near enough at 850 net calories while doing 450 calories worth of exercise and being 10-15 pounds above your goal weight and a 5'6" woman. That is the kind of deficit that might work for a very overweight or inactive person, but you're neither. Actually, a quick look at the BMI table tells me that you're not overweight, at all, and are in fact in the second percentile square of "normal". Your goal will put you in the second percentile of underweight.

You're bordering on anorexic here girl. You should probably rethink your goals. If you're not happy with the way you look think about body recomposition rather than weight loss. Eat at or even a little above maintenance and add strength training into your exercise routine. You don't need to lose weight, and you certainly don't need to lose 15 pounds.

I once was on a diet for months where was eating 1200 calories and less than 20 grams of fat a day, and working out for hours each day. I got seriously sick; I was fainting, my hair was falling out, my heart beat slowed...My nutritionist said I needed to be eating at least 1500 calories and 50 grams of healthy fat each day. Everyone is different, but 850 total calories is nowhere near enough to sustain somebody who is working out.