Understanding physiological adaptations to weight loss

Medical Q&A [Moderated]
1

Maintenance of lost weight and long-term management of obesity

I recently came across the linked study by Hall and Kanan which examines the difficulty of maintaining weight loss in the long term. Among some of the things the study proposes based were that for every 2.2lbs/1kg of weight loss, an individuals appetite can increase by up to 100kcal per day. That is staggering to consider but it does make sense, given that the effectiveness of GLP-1s (in part) wrt weight loss is around normalizing and suppressing appetite.

My questions to BBM are:

Given that obesity is now (even in those who do lose weight) behaves much more indicative of a disease, are we wasting time with focus being on adjusting the food environment and lifestyle changes?

Should much more efforts focus on pharmaceuticals interventions? Especially when they are (often) ridiculously effective?

My takeaway recently has been that even if food environment, lifestyle and exercise interventions are all in play, a large number of people who’ve been obese, have a number of layers of hormonal and biochemical issues stacked up against their efforts.

My last question:

Is there anything that can be done in between, lifestyle, environment, exercise, nutrition, etc and pharmaceutical interventions that can treat the maintenance problem?

Many Thanks

Winston

2

Howdy,

Yes, a number of changes occur in response to weight loss that ultimately limit energy expenditure (e.g. decreased NEAT) and increase energy intake (e.g. increased appetite). The magnitude of these effects vary greatly amongst individuals, and it is mostly genetics.

Whether or not you view lifestyle and environmental changes as a waste depends on your perspective. I think the evidence supports a change in environment being the proximate cause of obesity for most, given that genetics have been static obesity rates have tripled in the last 50 years. In that same time frame, portion size, energy density, availability/desirability of ultra-processed foods, and the number of meals consumed that are prepared outside of the home have all gone up drastically. If we could fix the food environment overnight, obesity rates would fall.

The pushback here would be we cannot make sizable changes in the food environment without policy change. While true, changes to someone’s individual food environment (at home, the office, etc.) all do seem to help promote healthier eating behaviors, which do have health benefits. I don’t think that’s a waste of time, though I don’t think it’s sufficient for most to adequately treat obesity either.

For lifestyle change, particularly exercise, one could argue (correctly) that exercise only has limited effects when it comes to weight loss. That’s true, but it is one of the most powerful tools we have when it comes to general health promotion, particularly when it comes to the pathogenic mechanisms of obesity, i.e. dysfunctional/ectopic fat tissue and biomechanical strain. Most people do not exercise and those who do don’t do enough, so if anything, we’re not “wasting” enough time.

I think the crux of your question is, “should we be using medical interventions more?” and my answer is yes. I think they work better than lifestyle alone for obesity, thereby reducing the risk from obesity better (and faster) .I also think they have unique benefits related to their pharmacology that exercise doesn’t seem to do much for, e.g. ectopic fat, substance use disorder, chronic kidney disease, etc.

To your last question, maintenance seems to be achieved with continued use of the medications for most.

We’ve talked a lot about this on many recent episodes of our podcasts and articles:

-Jordan

3

Hello Jordan and thank you for your detailed reply.

Just to clarify: I don’t think the pursuit of lifestyle or environment interventions are a waste of time either. I do think though that trying to change them completely when people are in the grip of battling obesity, receives too much emphasis in weight loss strategies, services and publications. Most people who have struggled to lose weight, do try these things and most are unsuccessful.

I am more of the belief now that the emphasis of interventions needs to change for many people. IE making activity and lifestyle changes accompany weight loss vs using it to drive it from the onset (wherein the excellent results of GLP-1s and other weight loss drugs do the initial driving.)

Far too many services focus on driving weight loss via activity and intense caloric restriction, with a prevailing idea common to many that willpower is most critical component. We now know this isn’t true.

Winston

4

I agree with you! Well said.