Food coma

People with multiple sclerosis are much more sensitive to sleepiness after eating. Why?

I have become aware that people with multiple sclerosis (pwMS) suffer from food coma or excessive sleepiness and fatigue after eating a meal. For normal people, we call this phenomenon postprandial somnolence or the siesta syndrome. Others refer to it as the ‘food coma’. 

We now have evidence that people with MS are particularly sensitive to postprandial sleepiness and fatigue. Are you? 

Postprandial somnolence (PPS) is a normal state of drowsiness or lassitude following a meal. PPS is a real phenomenon and has two components: (1) a state of perceived low energy related to activation of the so-called parasympathetic nervous system in response to the expansion of the stomach and duodenum from a meal. In general, the parasympathetic nervous system slows everything down.  (2) A specific state of sleepiness, which is triggered by the hormone cholecystokinin (CCK) that is released in response to eating and changes in the firing and activation of specific brain regions. The reflexes responsible for PPS are referred to as neurohormonal modulation of sleep through the coupling of digestion and the brain. The signals from the gut to the brain travel via the vagus nerve. What I am saying is that there is a well-studied biological reason why we feel sleepy after eating a meal. 


I have an index patient who alerted me to the problem of food coma in pwSM. She was so affected by PPS that she now only eats one meal a day; her evening meal. She does this quite late so that she can crash and sleep about an hour after eating. She is a professional and needs to be functional during the day and finds if she eats anything substantial in the day she simply can’t work because of her overwhelming desire to sleep. We have tried caffeine, modafinil and amantadine to counteract PPS, but these medications only had a small effect in counteracting her PPS and allowing her to work productively. Other patients reporting this have noticed some benefits from stimulants. Interestingly, my index patient, like a few others, find carbohydrate-rich foods particularly potent at inducing ‘food coma’

Physiologists think that not all foodstuffs are made equal when it comes to causing PPS and it appears that glucose, or sugar, induced insulin is one of the drivers of this behavioural response. I suspect this is why people who fast or eat very low carbohydrate or ketogenic diets describe heightened alertness and an ability to concentrate for much longer periods of time.

In a recent survey, we found PPS to be very common in pwMS; 88% reported suffering from food coma with 41% of respondents describing it as severe or severe and incapacitating. 

To manage your food coma could adopt the above extreme solution and only eat one meal per day. Clearly, this is not for everyone and is very difficult to implement. I say this, but many of my Muslim patients report feeling so much better during Ramadan when they essentially practice this type of eating behaviour. So you may want to give it a try. 

Another option is to reduce your meal size and cut out any carbohydrates from your daytime meals. You may find this difficult because it takes time for your metabolism to become optimised for ketosis.

Other pwMS find eating micro-meals helpful, i.e. instead of large meals you eat multiple small snacks during the day. In some cases, the judicious use of stimulants help. You can start with self-medicating with caffeine, but this may come with the downside of making your bladder function worse. I have found a small number of patients find modafinil or amantadine helpful. However, the evidence for this is anecdotal. We really need randomised trials. Please note you should probably not take stimulants later than about 3-4 pm as they have a long half-life and can cause insomnia.

Some of my patients have also reported that exercise has helped them deal with PPS. I am not sure how exercise works except by possibly lowering glucose and insulin levels and improving insulin sensitivity. The latter will reduce hyperinsulinaemia that will not only cause PPS but is an important driver and component of metabolic syndrome and obesity.

Be aware that PPS will be worse if you suffer from a sleep disorder and suffer from excessive daytime sleepiness already. Most pwMS have a sleep disorder so there is little point in focusing on PPS and ignoring the elephant in the room.

If any of you have hacked your own metabolism or behaviour and have found other strategies to deal with food coma please let us know.

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General Disclaimer: Please note that the opinions expressed here are those of Professor Giovannoni and do not necessarily reflect the positions of Barts and The London School of Medicine and Dentistry nor Barts Health NHS Trust. The advice is intended as general advice and should not be interpreted as being personal clinical advice. If you have problems please tell your own healthcare professional who will be able to help you.