Australians of every generation are reacting to everyday foods in surprising ways, from Gen Alpha breaking out in rashes from strawberries to Boomers developing IBS from pineapple.

A new analysis by FoodFit uncovered the top 10 food incompatibilities and symptoms for each age group, showing how food reactivity isn’t “one-size-fits-all” but shifts with life stage and cellular state.

How food reactions impact each generation

Food incompatibility is a lesser-known form of food reactivity. Symptoms flare up when ordinary foods temporarily disrupt an individual’s current cellular or inflammatory state, showing up as bloating, rashes, brain fog and headaches. Unlike allergies, which trigger a blood-based immune response, or intolerances, which stem from enzyme deficiencies, incompatibility aggravates existing imbalances.

And FoodFit’s latest data – where it aggregated 2856 hair sample tests conducted in the 2025 financial year – reveals those imbalances show up differently across the generations. The findings highlight that food incompatibility is inherently bio-compatible and what causes a reaction in one individual may be completely tolerated in another. It’s never a one-size-fits-all outcome.

“A food like strawberries or coffee might be fine for one person but can cause issues in another, depending on their cellular state at the time and life stage. For kids, it could be rashes, a teenager could suffer from unexplained headaches, compared to an older Australian who could be dealing with irritable bowel syndrome.”

Dennis Hodges, FoodFit Founder and CEO

What the FoodFit results say

FoodFit’s analysis found the top ten symptoms and incompatible foods (after bread and milk) across each generation.

• Gen Alpha (under-12s) – FoodFit’s analysis found that the top symptoms in Gen Alpha are skin and behavioural issues. Rashes and eczema top the list (11.6%), with constipation, hyperactivity and sleep issues close behind. Their main food foes? Strawberries (64.7% of this cohort), tomato paste (50.4%) and corn tortillas (46%).
• Gen Z (age 13–28)– This generation experiences symptoms linked to poor digestion such as bloating, headaches, diarrhoea and constipation. The foods most likely to cause them are corn tortilla (50.5% of this age group), chlorella (47.4%) and coffee (46.3%).
• Millennials (age 29-44) – The ‘cognitive crisis’ generation, where brain fog, tiredness and poor sleep are among the top complaints. These are fuelled by incompatibility with chlorella (48.7% of this cohort), strawberries (43.6%) and garlic (42.9%).
• Gen X (age 45-60) – This is where physical deterioration begins – and it’s the first time joint pain makes the top 10 list of symptoms. However, bloating, brain fog and tiredness top the list. These are aggravated by strawberries (50.8% of this age group), tortillas (49.2%) and chlorella (47.5%).
• Boomers (over-60s)– Irritable bowel syndrome is the top symptom after bloating, followed by reflux and flatulence. Boomers fare worst with foods often seen as healthy: pineapple (52.9% of this group), garlic (50%) and chlorella (50%) all appear in the top list of incompatibilities.

FoodFit’s Compatibility Program is available exclusively through qualified practitioners and involves testing for 600 foods and household items, plus a six-month guided elimination plan, at a one-off cost of $299.

Have you noticed changes in food intolerance symptoms over the years? Leave us a comment below.