My coach says that I need to eat 1.2 - 1.5 grams of proteins per kilogram when I have a common cold and flu. I normally eat one gram of proteins per kilogram, while double it when doing my exercise training.

He explained that the reason why you need to get more good proteins when you are sick is that the body is building antibodies by the adaptive immune system and later for innate immunity.

I think he can be right based only on my own experiences getting better from common cold with low protein diet - it just takes a lot of time, while under high protein diet, you get better faster. I also think his explanation makes complete sense to me, since antibodies and antigens are proteins.

Why do you need more proteins when you are sick?

  • $\begingroup$ Who says antigens must be proteins? Is this true? Many will be peptides of course but surely not all antigens are proteins. Anyway, you don't build antigens, whatever pathogen has infected you does. $\endgroup$
    – terdon
    Mar 25, 2013 at 20:47
  • 1
    $\begingroup$ no antigens don't have to be proteins, they can be a variety of things like pollen, chemicals, parts of a pathogen, or even endogenous components of cells (such as those which are targeted in autoimmune disease- so technically you can build antigens) and your body produces antibodies against them $\endgroup$
    – relf20
    Mar 30, 2013 at 11:19

2 Answers 2


Your body needs more energy when you are ill to facilitate the recovery process which includes the production of white blood cells to help fight the infection. This shouldn't be limited to proteins though, carbs are also very important as they are provide high amounts of energy. Basically just making sure you eat a varied and balanced diet is more important when you are ill to make sure your body receives the nutrients it needs to fight infection and heal itself. As it is having to work harder when you are ill it makes sense to eat more high energy foods. Micronutrients are also very important!

Minerals such as selenium and zinc work to keep the immune system strong. These minerals are found in protein rich foods such as beans, nuts, meat, and poultry. — Source

Although if your diet is varied you should be getting plenty of these anyway, without needing to take supplements.


Remember that your coach shouldn't give dietary advice unless he's trained as a dietician. Protein isn't as important as glucose really, that's the thing you burn the most. However you use everything: vitamins to tell the immune cells where to go, proteins to make antibodies, glucose to fuel millions and millions of neutrophils and other cells. Even fat stores may start to move in order to keep your glucose high but not too high. The excess protein is unlikely to do you harm, it'll just get urinated out typically. Minerals can be used by enzymes to make them active that are in charge of destroying bacteria.

So as a rough summary, eat healthily. Exactly how you should eat before getting ill to limit the duration or prevent symptoms in the first place. If you lack the minerals and vitamins during the time you're ill you probably lack them all the time round so don't change what you eat when you're ill, but change what you eat when you're well and then your body will have everything stocked up when you're ill and all you need to eat is glucose and drink plenty of fluids and if possible continue with the healthy stuff.


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