What turns on the body’s the starvation response (SR), a drop in the number of calories consumed or a decrease in the volume of food eaten?

Have any of you ever come across an answer to this question in your reading? I’ve read about the SR but I’m confused on this point. Some say that extremely low calorie diets work until the SR kicks in and slows or stops weight loss. If that’s the case, how is WLS successful? It seems like the reduced calories they can eat would invoke the SR and prevent the accelerated weight loss they experience. Then again, since it takes so little food for them to feel full, maybe the SR never kicks in?

Just something I’ve been wondering about.

The human body has quite complicated mechanisms. It is true that if you go on an extremely low calory diet you will loose weight pretty fast. In my case, when i started this kind of diet, it was nearly a pound a day.

HOWEVER:

After a couple of weeks weight loss slowed down and then it was around a pound a month. Furthermore i was getting weaker and weaker.

I think the whole point to weight loss is to have a moderate daily calory deficit. Values will be different depending on your present weight, age and level of activities. However, 1000 calories a day deficit represent a value that will get off the pounds slowly but surely, wihtout going into starvation mode.

It is also important to consider other values such as fat and sugar intake. 1000 calories intake will have a quite different if it is from a cheesecake or grilled chicken salad.

First let me say that I'm by no means an expert, and what I'm writing here is just how I understand that things work...

The starvation response that you are talking about is a decrease in metabolism that happens when the body is trying to compensate for losing weight. Your body doens't like to lose weight, it tries to hang onto the fat as much as possible as a survival mechanism. That is why so many people say to lower calories by a few hundred so that your body doesn't go into Starvation Mode. It has to do with calories tho, not volume, I think that was your first question.

WLS is kinda different, because not only does the surgery shrink the size of the stomach, it also bypasses a part of the small intestines so that not as much nutrients are absorbed. I'm not sure how this affects the metabolism, but I'm sure that such a dramatic difference in diet will effect it somehow.

But lets say a 400 lb person has weight loss surgery, the calories needed to maintain that weight (without any excersise) is around 3700 (according to fitday). This person starts taking in about 1000 calories because that is all they can physically eat, I'm not sure that the starvation response can keep up with that kind of dramatic change. WLS is full of complications and by no means should be takin on lightly. The best place to ask that question maybe the 3fc weight loss surgery forum.

But it's a good topic to discuss.

Hi! I don't know much about this -- which makes me want to go do some research! -- but I did want to just throw out there that not all people who get WLS DO have continued accelerated weight loss, as both slower metabolisms and unhealthy eating behaviors can still disrupt their weight loss. A lot of folks assume that the WLS, if successful, automatically gets them pretty much guaranteed dramatic weight loss, and that is not always the case.

I know this isn't really where you were you were going with your question (and I, too, care about the answer! ) and I know you just used WLS caloric intake and weight loss as an example -- but I did just want to mention it. The question of metabolism might still be relevant to your concern about the starvation response.

Good luck, and I'll be reading!

How about another non expert opinion
I'm a bit uncomfortable with the amount of time folks use the term "starvation mode".
I believe that it can happen, although not often enough for people to be afraid of it. I also believe that if you're not getting enough fuel, you'll slow down, feel rotten and stop losing weight.
For me ... the answer is increasing metabolism. I need more muscle mass. Another thing ... on 1200 cals, if I stopped losing, it was because I stopped walking. My basal is only about 1350 cals so I could subsist on 1200. But yuck! I like to eat too much for that. And actually I'm kinda enjoying exercise too. What a surprise that has been.

I entirely agree. No offense, MoveMoveMove -- I seriously don't mean anything personal here -- and I'm still interested in the answer to your question -- but truly, I think in general most folks should be more concerned with eating too much than eating too little. And, as Susan -- and a lot of the folks over at the Maintainers forum -- say, the closer you get to goal, the more and more important exercise becomes in either continuing to lose, or maintaining the loss. You can only go so low with the kcals, right?

But the starvation response thing occurs so infrequently in comparison to how much its concept is bandied about. I know it seems sometimes that people use it as an excuse not to go lower with their calories than they'd like.

Thanks everybody.

No Sarah, I'm not offended. It's just a question that I've been thinking about while reading some things on weight loss/eating plans.

I lurk on this site almost every work day and know that there are some serious and capable researchers here. Just thought I'd put the question out there and see if anyone had an answer. If I ever find it, I'll be sure to post it here.

Have a great day!

I have read that it is in response to hunger. My experience leads me to believe that. I started eating snacks (fat-free yogurt, bananas) between meals to avoid hunger, instead of avoiding them, and the weight began to come off. By keeping my blood glucose stable this way, it helps me avoid diet headaches, and keeps my energy levels up.