Q&A: Why Do Non-Paleo Foods Make Me Sick Now?

Here’s a question from a Paleo Plan member that you may have had yourself…

Hi, I have a question for you … I am having very positive results from the Paleo Plan, but now feel sick when I eat foods that are not on the Paleo Plan (grains, sugars).

Prior to Paleo, I never had this reaction to these types of foods. I’d like to understand why my body is now responding this way. Any information would be much appreciated.


Hi Nancy,

To be honest, I’ve never found a good explanation for why this happens. Trust me: you’re definitely not the only person this happens to, and it can be quite frustrating. But my theory is that it’s sort of like when you’re addicted to drugs or cigarettes or alcohol. Not to sound alarmist or overly dramatic, but you could liken gluten, dairy, and any other food that your particular body doesn’t do well with to any poison, such as drugs or alcohol.

So, for instance, if you’re addicted to alcohol for years and years, your body somehow adapts to it and goes into this maintenance mode. You don’t really feel that great, sometimes you have terrible hangovers, and you might have certain markers in your blood that show damage to your liver, etc. But you feel… ok. Then when people quit drinking, they often end up feeling better than they have in a long time. Lighter, more energetic, more clear-headed, less depressed. They might even lose weight, and their blood markers start normalizing again. And when they DO drink after they’ve quit, they often feel it way worse than they ever did when they were drinkers. Same with cigarettes. A lot of people can’t even stand the smell of cigarettes after they’ve quit for good.

I think we develop a tolerance for things in our bodies. You (like so many other people) probably felt a little worse when you were eating foods your body didn’t like. Overall, on an everyday basis there may have been a shadow over your health, right? Maybe regular headaches, constipation, bloating & gas, fatigue, depression, or some combo of those? Those are the most common symptoms I hear about. And then when people go Paleo, those things generally go away, or at least improve. So it’s kind of like taking away the alcohol–the poison–from your body and letting it clean itself up.

Then when you eat those old foods again when your body is all “clean”, it feels terrible! Worse than it ever did before. But it’s because your body’s immune system, liver, and everything else are able to fight back against something harmful because they’re stronger and more alert. They’re no longer in that maintenance mode – that “I’ll guess we’ll just lay down and take this abuse” mode. That’s how I see it anyway. In my opinion, those strong negative reactions to those old foods are just a further indication that you’re doing the right thing.

I wish I could give you more of a scientific response, but at this time I don’t have one. I hope this helps, though! Please let me know if you have any questions.



  1. I often wonder if the gut flora we have that is specific for the foods we cut out dies back somewhat when we don’t “feed them” anymore. Then on top of the response you mention we get an additional “can’t digest THAT!” reaction. Worth considering?

  2. As a medical technologist working in a hospital lab culturing too many patients, the ‘feed them’ though it sounds good just doesn’t ring true. The patients who had the worst issues were the ones who were taking antibiotics or other highly toxic chemicals. These chemicals destroy your ‘normal’ flora and allow other microorganisms to take over. I also work in immunology and though my experience is limited here, what Neely writes is very close to an immune response. That’s to say that when the body sees something the first time it may not react or when exposed constantly you stay at a heightened response. But then when you remove it for awhile and then are exposed again the reaction is as positive or more than the previous time. This is what happens to people with peanut and other allergies. Each time they come in contact with the ‘irritant’ they can have a much worse reaction. That isn’t to say each time you eat gluten it will get worse but it does explain why other foods seem to bother you more. Sorry for being long winded. Any immunologist have a better explanation?

Leave a Reply