Kandace Knudson, PhD, MPH

The question about nutrition I get asked most often is: "Should I eat vegetables?" Let's end the debate once and for all. Vegetables contain two opposing forces at the same time. On one side: polyphenols, carotenoids, glucosinolates, fiber, essential vitamins, and minerals that lower inflammation, feed your microbiome, and protect against chronic disease. On the other: lectins, oxalates, phytates, and fermentable fibers that can irritate a damaged gut, trigger immune flares, and block mineral absorption. The mistake is treating vegetables as universally good or universally bad. The body isn’t that primitive as it responds differently depending on the state of your gut, your immune system, and your exposure pattern. Now, here’s the interesting part. Plant compounds are hormetic stressors. Low, pulsed, varied exposure activates NRF2, boosts antioxidant defenses, and strengthens resilience. Constant, high-dose, repetitive exposure does the opposite, i.e. overstimulation, irritation, and, in sensitive guts, full-blown inflammation. And this is why vegetable cycling works so well. A short elimination phase, 2 to 4 weeks of low-lectin, low-oxalate, low-fiber eating, calms mast cells, reduces permeability, and lets the gut wall repair. Clinical IBS research shows measurable improvements in barrier function after this type of reset. Then, reintroducing vegetables in structured rotations gives you the upside of phytochemicals without the cumulative downside of anti-nutrients. You get the NRF2 activation, the fiber-driven SCFA production, the micronutrient bump, and the microbial diversity without overwhelming the same pathways day after day. Think of it like strength training. You don’t hammer the same muscle seven days a week. You stress it, you recover, and you rotate. Gut physiology is no different. People with IBS, SIBO, autoimmune flares, or a history of food sensitivities often benefit the most from this model. But even robust metabolisms adapt well to cyclical exposure because it mirrors ancestry, seasons, food availability, and the natural ebb and flow of plant toxins in the wild. The real danger lies at the extremes. If you eat spinach daily, you’ll saturate yourself with oxalates. Beans? You’ll overload lectins. Eliminating plants forever? You’ll starve the microbiome and lose the phytochemical signals that keep cellular defenses sharp. Take the balanced approach: Reset. Rebuild. Rotate. Use plants strategically, not religiously. Use removal as a tool, not a lifestyle. Use variety as your shield against sensitisation. Vegetables aren’t inherently good or bad, they’re stimuli. And the body thrives when stimuli arrive in intelligent, periodic waves.