Why Can You Eat a Food One Day... But React to It the Next?

The Full Glass: Why cutting out more and more foods isn’t always the answer

If you’ve ever struggled with food sensitivities, you’ll know how confusing they can be.

You eat something one day and feel perfectly fine. A few days later, you eat exactly the same food and suddenly you’re bloated, itchy, exhausted, headachy, or your digestion has gone haywire.

Naturally, we blame the food.

So you cut it out. Then another food seems to cause problems, so that goes too. Before long, your list of “safe” foods is getting smaller and smaller, and you’re starting to wonder what on earth you’re supposed to eat.

One thing I often explain to people in my office is that the food may absolutely be contributing to your symptoms — but it may not be the whole problem.

The Full Glass

I explain this using something I call The Full Glass.

Imagine your body is like a glass. Every day, different stresses are adding into it. Food can be one of them, but there can also be poor sleep, stress, chemical toxins, nutritional deficiencies, or hidden immune challenges such as viruses, bacteria, parasites, yeast or mould.

Some days there’s a little more room in your glass. You eat the cheese and nothing much happens. Hooray!

But three days later, your glass may already be almost full. Perhaps you slept badly, your digestion isn’t working as well, or your body is dealing with other underlying barriers you may not even be aware of.

Then you eat exactly the same cheese and ba-boom — your glass overflows.

Now it looks as though you could tolerate cheese on Tuesday, but suddenly you can’t tolerate it on Friday. No wonder food sensitivities can be so confusing.

The cheese may absolutely have contributed to the reaction. But it was the final drop that tipped your already-full glass over the edge.

So naturally, the cheese gets the blame.

But it usually isn’t what filled your glass in the first place.

And this is where people can get stuck. They remove the food that caused the latest reaction, then the next one, then the next, without asking the bigger question:

Why is my glass so full in the first place that I’m struggling to tolerate these foods?

What can you do yourself?

There are some simple things you can do to start gathering clues rather than continuing to cut out more and more foods you think might be causing the problem.

1. Look for patterns — but don’t expect them to be obvious

If you have a symptom every day, there’s often something you’re eating every day that’s contributing to it.

The trouble is, if you’re eating that food regularly and your symptoms are there most of the time, it can be incredibly difficult to spot.

One of the most common things people say to me is, “I can’t tell what I’m reacting to. Everything seems to cause a problem.”

So don’t worry if the answer isn’t obvious. At this stage, you’re looking for clues.

2. Try the 14-Day Test

For 14 days, write down everything that goes past your lips and record your symptoms alongside it.

Don’t rely on memory — most of us are terrible at remembering exactly what we ate three days ago.

Sometimes a pattern starts to appear. Perhaps every time you eat bananas, your bloating becomes much worse, your skin flares up or you develop a headache.

That’s useful information. You can remove that food for a period of time and see what happens.

3. Watch what you replace foods with

This is something I see all the time.

You cut out cow’s milk and start having oat milk every day instead. Or you go gluten-free, but inadvertently start eating a lot more corn because it’s in so many gluten-free products.

It’s very easy to remove one food and unknowingly replace it with another food that may also be contributing to your symptoms.

4. Remember that food reactions aren’t always immediate

Don’t automatically blame the last thing you ate.

Some food reactions can be delayed, which is another reason they can be so difficult to figure out.

Look back over your food and symptom record and see what’s been happening over several days, rather than only looking at the meal you ate immediately before your symptoms became worse.

And if you still can’t see a pattern, that doesn’t mean there isn’t one. When several foods and other underlying factors are contributing at the same time, it can be incredibly difficult to untangle it yourself.

If food isn’t the whole problem, what else is filling your glass?

By the time someone comes into my office with a long list of food reactions, I’m rarely looking at food alone.

There are often other things adding to the load and making it harder for their body to tolerate foods that perhaps weren’t a problem in the past.

These can include nutritional deficiencies, chemical toxins, heavy metals, scar interference, or hidden immune challenges such as viruses, bacteria, parasites, yeast or mould.

More often than not, I find a combination of underlying barriers getting in the way.

Removing foods that are aggravating your symptoms can absolutely help take some pressure off your body, and sometimes you need to do that for a period of time.

But the goal isn’t to keep removing foods until you’re practically living on the lettuce and rice diet.

We also need to ask what else is filling your glass and why your tolerance has become so low in the first place.

What this can look like in real life

One client who came to see me had been struggling with frequent, urgent diarrhoea.

It had reached the point where she was nervous about going out. She knew where the toilets were wherever she went and carried a change of clothes with her, just in case.

Eating had become frightening because so many foods seemed to trigger the diarrhoea. She had already cut out a number of foods and tried several gut-support supplements, but some had actually made her symptoms worse.

Eggs were an obvious trigger. If she ate them, she could be rushing to the toilet soon afterwards.

In the beginning, we did need to remove some of the foods she was reacting to, but that was only part of the picture.

As we identified and worked through the underlying barriers that were getting in the way of her gut healing, things gradually changed.

She can now eat eggs again. Yippee!

When I saw her recently, she told me she no longer carries a change of clothes or plans her outings around where the nearest toilet is.

We’re still working on healing and repairing the damage created by those underlying issues, but life today looks much better.

And that, to me, is the goal.

Not simply cutting out more and more foods you can no longer tolerate, but working towards your body functioning better so you can tolerate a much wider variety of good, nourishing foods — and enjoy eating again.

When it may be time to look a little deeper

If you’ve been cutting out more and more foods, your symptoms are still there and you can’t work out what you’re reacting to, it may be time to stop focusing only on the food.

Using Nutrition Response Testing™, I assess which foods may be aggravating your body right now, while also looking for the other underlying barriers that may be getting in the way of healing and repair.

The aim isn’t simply to give yo

u another list of foods you can’t eat.

It’s to work out why your glass is so full in the first place and what we can do to start taking some of that load away.

If you’re tired of guessing, cutting out more foods and still not understanding why you’re not improving, this is exactly the sort of thing I help people work through in my office.

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