What are the *risks* of losing weight (when overweight)?

This posts relates solely to people who are overweight or obese and who have excess weight to lose. Those who are at a healthy weight have different risks from losing unnecessary weight.

I've sent an email to the World Obesity Federation to ask. My sciencey background never brought up this facet of weight gain / weight loss but I have occasionally wondered. If transporting fats around the body when putting on weight can lead to atherosclerotic damage and high blood pressure can't the same thing happen when losing weight as, from a 'transport infrastructure' point of view, there's no difference - fat, in the form of lipoproteins, is whizzing around in the blood whether it's about to add to or be taken from adipose tissue.

Here's what I sent, if I get a reply I'll add the gist of it.

I am trepidatiously adding 'weight loss' to the labels for this post, knowing that this will very effectively bring a lot of spam commenters to my yard ;)

 

 

Hello :)

I'm curious to know about the risks of losing weight (the benefits seem fairly obvious). As a fat person I have plenty of fat stores, which initially grew because fats (directly or derived) from my diet would have been transported around in my blood and eventually stored in various adiposits. Presumably some will also have been laid down atherosclerotically en route. Bummer. I expect we'll find out in a few years. Probably not that many as I'm 51.

If I begin to lose weight wouldn't the exact same process happen in reverse? A bit of metabolism will free up some of my lard which will then lipoprotein its way around my bloodstream before eventually being breathed out as CO2. Presumably in doing its circulatory rounds some of it could also contribute further to any atherosclerosis.

So is losing weight quite a dangerous undertaking? Prevention certainly better than cure I suppose.

Also, would I then flood my system with all the fat-soluble vitamins? Not too bothered about D or K, but I might want to avoid self-overdosing on Vits A And E. Presumably there will be other fat-soluble things that pop out into my bloodstream, much like a molecular version of ancient mammoths being released from the melting permafrost.

My retweet of a tweet in a thread by Foone about composting the
rich, rather than eating them (Compost the rich, don't eat the rich)

Presumably in returning to my bloodstream these fats will make it thicker and stickier, adding a blood pressure risk to weightloss proceedings. Possibly one should lose weight very slowly. Or maybe take blood thinners while doing so.

I'd also presume that the relative risk weighs (ha!) more in favour of losing any excess weight but I don't think I've ever seen this aspect of risk considered. 

Can you point me to any research in this area (I have a degree in biochemistry* and have worked in a lipid chemistry lab so am comfortable with academic literature).
 
Thanks
Jo

*Pedantically my degree is B.Sc (Hons) Combined Studies because that's what the modular degree was called (you could also do Combined Arts). My degree is in Biology, Psychology and Computer Science. I then did a Masters degree in Neuroscience. Given that neuroscience kinda covers biology, psychology and computer science you might imagine some great intentional plan but no - entirely by accident. I don't think I'd even heard of the word neuroscience until graduating and someone suggested it as a (suddenly rather obvious) follow-up.