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Leptin, Fat Cells and Weight Gain: Insights from ObesityWeek 2019

Nov 20, 2019



Voila! The rest of the new and noteworthy tidbits of info I collected from ObesityWeek 2019.


Impress your friends with facts about fat cells, a hunger hormone, and weight gain in pregnancy and after surgery (or just forward them this update and have a stimulating discussion!)




A Fat cell (adipocyte) is born.


Then if we take in more fuel than our bodies need, it gets bigger and bigger. And more join the party.


As they continue to grow in size and number the fat starts to need a blood supply.

(This is like a town growing into a big city that needs more organized water and power supplies and other infrastructure.)


Then, if we continue to eat more fuel than our body needs, the fat tissue gets so bloated it cuts off it’s own blood supply which leads to tissue damage, inflammation and eventually, fibrosis.


The bad news:

  • Adipose inflammation leads to insulin resistance in the whole body.


  • Once the fat tissue is fibrotic it’s more resistant to weight loss.


The good news:

  • When we lose weight we can undo all of this.


  • In the meantime, physical activity decreases adipose inflammation.




New research shows there are better outcomes for the baby (in terms of risk of small size and premature birth) when overweight and obese women who get pregnant don’t gain any (or very, very little) weight during the pregnancy.


This does not mean “a diet”. No weight loss during the pregnancy.   It just means eating healthy foods in the amount the pregnant body needs to stay steady.


In essence they were losing fat during pregnancy, since they were staying the same weight while having a baby grow inside them.


In light of the info above, they were decreasing the overall inflammation in the body which is likely beneficial.


More good news, if they hadn’t gained weight during pregnancy, they seemed to be able to lose weight easier after the pregnancy, too.




Leptin is the hormone that’s released from fat cells that tells the body to stop eating and start moving.


When you add more fat cells, you add more leptin into the bloodstream.   This seems to make sense, more fat cells, more hormone to try to get back to baseline.


But it turns out more leptin in the system leads to leptin resistance and then leptin is less effective.


The new finding is this: the less leptin the better.


When you lose fat, your leptin levels decrease and the leptin sensitivity increases allowing the hormone to work effectively.


Dashed are the hopes of a leptin injection to solve our woes. Back to the drawing board.




The biggest predictor of weight gain or failure to reach expected weight loss after bariatric surgery is the amount of grazing a person does.


Grazing means eating small amounts of food throughout the whole day. In contrast to eating 3 meals and one or two snacks.


Grazing behaviors allow more calories in and therefore thwart fat loss.


While it’s a risk factor for post-bariatric surgery patients, we can all learn a thing or two here: it may feel like you’re only eating a little, but snack calories add up.




Join me today at 12:30pm PST on the Facebook Page, Stephanie Fein MD, to hear more details on these fascinating findings.