Please sir my MORs want a little MORE

Are you trying to keep your appetite in check through willpower ? Make sure to load up your plate with protein if you want to stop the give me MORs.


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Mobilize your MORs

Piece of meat firing off a canon displacing endorphin

Are you trying to keep your appetite in check through willpower ? Make sure to load up your plate with protein if you want to stop “the give me MORs”.

Are you trying to keep your appetite in check through willpower ?

Let’s face it – this approach is do-able, but DIFFICULT.   Generally speaking you can keep it going for a while, maybe long enough to fit into that special dress for a significant occasion.  But overriding your body’s hunger drive using psychology,  is hard work and probably doomed to eventual failure.

This is why yo-yo dieting is the norm, not the exception.

It’s much easier if you use a little body chemistry,  to keep your appetite in check and this is where protein comes in.

The power of protein

As a rule, protein foods tend to fill you up.

You may have noticed, when you have an egg on toast for breakfast, you  can more often than not, keep going till lunchtime, but a huge bowl of cereal, often leaves you with the mid-morning munchies.

So what is behind the “I am full” message that accompanies protein dinners ?

Unpacking the science of FULL

Some years ago, a team of French scientists figured out how proteins do this and MORE.

The more is particularly relevant to you, if you are insulin resistant.  It involves putting  the brake on hepatic gluconeogenesis. Something that is not happening quite the way that is should, when you’re insulin resistant.

In fact, this fail is the reason why metabolically broken people can’t regulate sugar levels very well.

The insulin response is not enough, to put away the current sugar delivery and keep up with handling he sugar being produced by the liver.   The story starts with your MORs……

Protein dinners interfere with MOR signalling

So what are MORs ?   MOR may look a lot like MORE, but I did not accidently leave off the E.  MOR is a short hand way of referring to the mu-opioid receptors.


Ironically, the MOR receptors do actually work like a MORE switch.

brain diving into the cookie jar under the influence of endorphins

When they get triggered, you typically want more to eat.

Now this may come as a little bit of a surprise….

Opioid biology

Opioids are normally associated  with happy head feelings, not gut feelings – think heroin and morphine.

cartoon versions of opioid drugs

But it turns out, mother nature includes MOR receptors in a variety of spots around the body.  The spot that is triggering the MORE eating, is  a set of MOR receptors lining the major blood vessel, known as the hepatic portal vein.

hepatic portal vein the bridge between the intestine and the liver

The hepatic portal vein is  responsible for transporting the nutrients and things,  that have been fished out the intestine to the liver.   The liver then cooks up a storm, dishing out nutrients to the rest of the body.

Bits of protein jam up MORs

When proteins, such as meat and milk are digested, they get broken down into smallish bits of protein, referred to as peptides.    As these peptides make their way from the intestine to the liver, they encounter the MOR receptors, which are embedded in the portal vein wall.

Now it turns out,  some of them slip inside the nooks and crannies of the MOR receptors.

The  presence of the peptides is duly noted, by the MOR receptors, BUT the MOR receptors don’t get upset.  Who does get upset are the endogenous opioids,  that are being produced by the neurons and endocrine cells.

The tiny little peptides end up jamming the receptor.

a very irritated endorphin unable to get onto it

Making it impossible for your endogenous opioids to DO THEIR JOB.

So what do endorphins do ?

The chill pill

Well officially they control gut motility and secretions, generally speaking, they slow things down :

  • inhibiting gastric emptying,
  • blocking peristalsis and
  • inhibiting ion and fluid secretion.

This is why people who take opioids to relieve pain, often end up with SERIOUS constipation, which is very difficult to relieve, because the tools of the laxative trade, find it very hard to work around this slow down.  Very hard !

NOTE : On the flip side…………. it works like a charm, when you have the runs,  think Immodium®, but that is a story for another day. 

A communication breakdown

We’re interested in what happens to the signalling being sent from the gut to the brain, the point being….

It DOESN’T HAPPEN, when the MORs are being jammed by the little peptides.

With the MORs  not sending a signal to the brain, demanding MORE to eat,  the hunger neurons get to take a load off, while the satiety neurons do their thing.  As long as these peptides are interfering with MOR activity, you feel pretty full i.e. you appetite is suppressed.

A peek inside the region of the brain controlling hunger

NOTE :  It doesn’t last indefinitely, clean up crews, remove the wayward peptides.

MORs and miracles

The MOR story has come to light  years ago, when the French research team genetically tinkered with mice so that they were missing MORs.  The MOR minus minus  mice, showed no signs of “feeling full” following a high protein meal, but since then……….the MORs have been implicated in the MIRACLE of bariatric surgery.  I’ll share more in an upcoming post.

Since human MORs are a lot like mouse MORs.

It’s likely the inhibition of MORs is one of the things contributing to humans feeling  full, following a protein meal, there are other factors, including changes in the volume of the stomach and the release of a variety of gut peptides eg.  cholecystokinin.

NOTE :  Safely accessing the hepatic portal vein in humans is a  BIG challenge, so there are still a lot of question marks around this biology in humans.

Jam your MORs

So to keep a check on your appetite, you want to jam your MORs, more often than not.  An added benefit of  using this strategy to put a brake on your appetite, is it switches the sugar production machine in the liver OFF.

Down grading hepatic gluconeogenesis – cuts insulin some slack.

When he springs into action, the only glucose he has to deal with, is the glucose you just ate.  This minimizes post prandial sugar spikes.

Making everyone a little happier.

Until next time round…..

Blocking MORs with meds

Now, you can block those MORs with meds, such as naloxone (Narcan®).  Naloxone is a drug that is designed to antagonize i.e. block the MOR receptors. The way that it works, is it has the right size and shape, to hop on the MOR receptor, but when it does……………..NOTHING HAPPENS.

naloxone firing off blanks

This family of drugs is usually used to help people dealing with an OPIOID crisis.

But in the DARK UNDERWORLD, they are also used as appetite suppressants.  But, you don’t need drugs to do this, just make sure when you load up your plate, you include a healthy dollop of protein, by obeying the rule of thirds.

Obey the rule of thirds

You might already do this at dinner time,  but  to really get the benefit, you want to apply this principle EVERYTIME you eat.


Especially if you are metabolically challenged.

A bonus benefit

Talking about in betweens, the added benefit of including protein in your snacks, is if you are feeling  flat, munching a bit of protein will also ring the brain’s alarm clock.  It’s a two for one deal, better brain chemistry and better body chemistry.  Watch this video to learn more.


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Mu-Opioid Receptors and Dietary Protein Stimulate a Gut-Brain Neural Circuitry Limiting Food Intake.  Cell (2012) 150(2):377-88. Celine Duraffourd, Filipe De Vadder, Daisy Goncalves, Fabien Delaere, Armelle Penhoat, Bleuenn Brusset, Fabienne Rajas, Dominique Chassard, Adeline Duchampt, Anne Stefanutti, Amandine Gautier-Stein, Gilles Mithieux. 

Further reading

fasting hyperglycemia

What causes fasting hyperglycemia ?

In the middle of the night, muscles aren’t busy and the brain is taking it easy, so when your live makes sugar, it has nowhere to go, giving you fasting hyperglycemia

Want to discover more ways to create BETTER BODY CHEMISTRY ?

Author: Taylor Payne