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Why “Eating the Rainbow” Works — And What It Actually Means for Your Health

January 26, 2026

You’ve probably heard the advice to “eat the rainbow,” but let’s be honest—that can sound more like something you’d tell a kindergartner than a full-grown adult trying to take their health seriously.

Here’s why it’s not kids’ stuff: Color is one of the easiest visual cues for “phytonutrient” diversity. Phytonutrients are natural compounds in plants that help protect them from UV radiation, insects, infection, and environmental stress. 

In humans, those same compounds support your health in ways that affect everything from inflammation and metabolism to mood and cognitive function. 

When researchers at Colorado State University studied people who ate the same total amount of vegetables, they found something important: the people who ate a wider variety had more markers of cellular protection, even though the quantity was the same. The difference was diversity.

Each plant family brings its own “toolkit” of phytonutrients. 

• A carrot gives you a mix of phytonutrients you don’t get from broccoli.
  
  
• Broccoli, in turn, is richer in certain phytonutrients than carrots.
  
  
• And onions provide phytonutrients that are hardly present in either carrots or broccoli.
  

Want to learn more? My new free guide, The Phytonutrient Cheat Sheet,  shows you why a more diverse mix of plants can meaningfully improve both your physical and mental health.

Because the more you understand the “why,” the easier it becomes to stay consistent with the “what.” 

Download the Free Guide