Starvation Mode - A really good Explanaion

OneDimSim

I see Starvation Mode debated sooo much on this forum - i googled it - and about 5th in the results came up a post from ThreeFatChicks Website - it is just so amazingly well written and on-target that I wanted to re-post there (OP did not have contact info, so I really hope she does not mind!) Hope others find it useful in a way of explanation as well.

Starvation mode doesn't prevent starvation, it only delays/prolongs the process.

Metabolism erosion is real, though there is no magic number at which it occurs. Some people may experience metabolism declines at 1200 calories or at 500 or not at all. It may take chronic dieting to trigger the process.

But it is "real" and anorexia and weight loss surgery patient experiences actually proves the theory, rather than disproves it. While it's true that both anorexic and wls patients lose weight on vldc's (very low calorie diets) they generally do not lose it as quickly as one would expect if metabolic erosion did not occur. If our metabolisms can be compared to a furnace, the less fuel we use, the more efficient the furnace becomes - the fewer calories it takes to keep us alive.

One of the ways this is seen is in anorexics is in the development of lanuga (a downy "fur"). Without body fat to regulate body temperture, the lanugo develops so that the body wastes less energy (fewer calories) on maintaining body temp.

Put a thousand people on the same starvation-calories, and some will die in weeks, some will die in months, and some will die in years. What accounts for the differences? In some cases, we know that metabolism erosion is in effect, because people tend to die much quicker of acute starvation than of chronic starvation. A person who's always been well fed will die much quicker of starvation generally than a person of the same age, weight, and health status who has experienced periods of famine in the past (either naturally or self-induced through dieting).

Without metabolism erosion as an explanation, the only way wls patients SHOULD be able to regain all of their lost weight is through intense effort. Because parts of the digestive system are bypassed, in theory (if metabolism weren't reduced) the person wouldn't have to change their eating habits at all to be able to lose at least some weight - this doesn't seem to be true. It also should be impossible for them to regain to become heavier than they were before surgery - at least not without eating TONS more than when they started. Again, this doesn't seem to be true. If a wls patient returns to their old habits, they don't just regain some of their weight, they regain all of it and often MORE. Another common occurence of wls patients who regain all their weight or even more - is that they're not eating more than when they started. In fact, they're eating less... but not enough less to adapt to their lower metabolism.

Not all wls patients experience the same degree of metabolic erosion. Some may experience little or none, and will lose their weight extremely quickly. Others on seemingly identical calorie levels and activity levels, may lose more slowly, sometimes much more slowly.

If metabolic decline werent "real" it would be virtually impossible for most bypass wls patients to regain all of their weight, but the failure rates are as high as 40% for some surgeries. And there's no evidence that these people are eating more than when they started, in fact most seem to be eating less than their presurgery weight.


I know for myself, my metabolism has slowly eroded over the years. The calorie-level it takes for me to lose 1-2 lbs a month would net me 5 to 8 lbs PER WEEK. The metabolic calculators used to be fairly accurate in estimating my weight loss in my 20's and now they overestimate my metabolism incredibly.

I haven't become starvation-proof, but I have become starvation-resistant. As a result, I would have a survival advantage in a starvation scenario, not related to my fat. Sure my fat would be starvation-insurance, but because of my lifetime of yoyo dieting, I probably have some extra insurance so that I'd likely outlive someone exactly like me who had never dieted (so of 46 year old, 289 lb women, with similar health issues, I'd have the advantage).


It doesn't mean that 1200 calories or any other number is "magic," but it also doesn't mean that metabolic-erosion isn't possible - or preventable. It means that getting weight under control early, in the fewest attempts, with the least amount of calorie-restriction probably is the best way to prevent or at least minimize metabolic erosion. It's likely that some people are more prone to metabolic-erosion, so some yoyo dieters may experience less metabolic erosion than others, but it still makes sense to "stack the deck" as much as possible.

I don't know if metabolism-erosion is reversible. There's some evidence that it's at least partially so (exercise enhances metabolism, so you can "earn back" some of your metabolic functioning with increased exercise, especially with muscle-building).

On one hand, it's important not to become deluded by the myths of starvation mode, but it's also important not to dismiss the realities. Starvation is a variable process, but chronic calorie restriction is one of the pertinent variables. It's great if you can drastically cut calories and not experience the metabolic decline that can come with it - though in my case the erosion was so gradual that I didn't notice it.

I didn't one day wake up with a crashed metabolism. Instead, returning to the same diet/calorie levels produced smaller and smaller results. I didn't go from losing 8 lbs a week to 1 lb a month overnight on 1800 calories and at 350 lbs.

Instead, I gradually lost the calorie-burning power. Maybe I'll regain quite a bit of it, but regardless I'm stuck with the metabolism I have and can't return to the metabolism I used to have.

However, it does make me very aware that I have to make this work, because I can't afford my metaboism to drop any further. And metabolism erosion isn't simply a more efficient furnace. When the "budget" get's cut, processes like immunity suffer. My immune system is severely compromised, probably because of the chronic dieting. There's quite a bit of evidence that immunity is one of the first budget-cuts the human body makes when calories become scarcer (which is why most people don't actually die of starvation, they die of infectious disease and other immune disfunction, because their bodies have "cut the funding" to the immune system).


None of this means any part of the process is magic or starvation-preventing. And all the evidence suggests that there's a tremendous variation in how individuals respond to calorie restriction.
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