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For years, nutritionist Katherine Lawrence was best known for something else entirely: using a plant-based diet to improve her reproductive health problems. That story became her calling card for almost two decades, long before her work in nutrition for neurodivergent kids began.
Then her family’s life changed. Her middle son was diagnosed with level 1 autism, ADHD, and OCD. Her husband, approaching 50, received a diagnosis of severe ADHD. Lawrence herself has long lived with OCD, which runs in her family.
Read more: Which Nutrients Can Improve Mood? A Plant-Based Guide To Mental Health
Suddenly, food wasn’t just about hormones or chronic pain. It was about meltdowns, focus, sleep, self-control, and how a neurodivergent brain responds when it does or doesn’t get the nutrients it needs.
The Physicians’ Committee for Responsible Medicine (PCRM), known for its YouTube channel, recently shared a video offering information on how food can both positively and negatively affect neurodivergent people. In that episode of The Exam Room podcast, Lawrence explains how years of trial and error in her own household led her to a new mission: helping parents use nutrition to support autistic and ADHD kids without pretending diet is a “cure.”
“I don’t want to mislead [you into thinking] that nutrition can cure anything,” she says. “This is a neurological difference [that is] largely genetic. But nutrition does affect how our body and our brain work.”
Lawrence’s lived experience with neurodivergence
Lawrence’s connection to the topic is personal and deep.
With three of the five people in her home now neurodivergent, Lawrence says it completely shifted how she parents, and how she thinks about food.
At first, she assumed certain behaviors were discipline problems or “middle child” issues. Over time, she realized the problem wasn’t willpower, it was biology.
“It really was just that his brain was not getting the nutrition support it needed,” she says. “It methylates [sic] different nutrients in a different way, and so he really just needs more nutrition support than the others.”
Her goal now is not to “normalize” her son, but to help him understand himself, reduce distress, and protect his long-term health. “I need to equip my son with self-awareness,” she says, so he can recognize triggers and navigate the world with a brain that works differently, and has some real advantages when it feels supported.
Processed food, sugar, and the gut–brain axis
A lot of parents assume the main villain in kids’ diets is sugar. Lawrence agrees it’s a problem, but she says it’s only one part of a much bigger picture.
Recent figures suggest that around 70 percent of U.S. children’s calories come from ultra-processed foods and sugar-sweetened beverages. Those foods affect blood sugar, mood, and metabolism. But for neurodivergent kids, Lawrence says, there’s another critical issue: self-regulation.
“Some of these processed foods, especially the sugary ones, trigger overeating,” she explains. Her son might eat until he’s in pain, then lie on the floor holding his stomach. The combination of sugar, refined ingredients, and additives overwhelms his ability to self-soothe and stop.
On top of that, ultra-processed foods often deliver a cocktail of preservatives, dyes, and other chemicals that Lawrence says “overpower his brain.”
To understand why this hits neurodivergent kids so hard, she points to the gut–brain axis. “The gut is our second brain,” she says. According to Lawrence, a healthy microbiome constantly communicates with the brain via the vagus nerve.
Around 90 percent of serotonin is produced in the gut, influencing mood, happiness, and behavior. About 50 percent of dopamine is also produced there, shaping focus and attention. If the gut is inflamed or out of balance, those neurotransmitters can drop, and neurodivergent kids, whose brains already have increased needs, may struggle even more.
Fish, dairy, and preservatives: hidden neurotoxins in kids’ diets
When parents look for “brain food,” they often turn to fish and fish oil, but Lawrence warns that these can be risky for neurodivergent kids. “What we miss are some well-known neurotoxins,” she says. “Mercury and dioxins, these are rampant in fish.”
She cites research showing that women who eat the most fish during pregnancy, and children who eat the most before age four, have the highest rates of ADHD. These toxins, she explains, can harm a developing brain. Fish oil supplements carry similar contamination and stability issues, so in her house, she uses microalgae oil instead, which is a clean source of EPA and DHA that she adds to her son’s smoothie.
Dairy is another concern, especially for kids with autism and ADHD. The main protein, casein, is hard for many people to digest. (About 65 percent worldwide, and even more among neurodivergent individuals.) When it’s not properly broken down, it can disrupt the gut microbiome and worsen mood or behavior. Lawrence says this is why many families see success with dairy-free, casein-free diets.
She also warns about PCBs, industrial chemicals that linger in soil and concentrate in animal fat. “They’re a known carcinogen. They’re known to affect the brain,” she says. When cows consume contaminated feed, up to 75 percent of those PCBs are released through milk and become further concentrated in cheese. Combined with digestion issues, she sees dairy as a double hit affecting both the gut and the brain.
Key nutrients for the neurodivergent brain
If certain foods can make things worse, which ones help? Lawrence focuses on a handful of nutrient groups that the research – and her kitchen – keep pointing back to.
She starts with omega-3 fats from plants and algae. Flax seeds, chia seeds, hemp hearts, walnuts, soy foods, and greens all make regular appearances in her family’s smoothies and meals. For a direct boost of EPA and DHA, she adds microalgae oil instead of fish oil, which she says provides a healthy source without the toxins.
Berries are another staple and what she calls “brain food.” Rich in vitamin C and phytonutrients, they’ve been linked to sharper focus and long-term brain protection.
Leafy greens come next. They’re packed with folate, magnesium, and calcium, which support mood, memory, and neurotransmitter function. When Lawrence’s son resists chewing them, she blends them into soups or smoothies.
Finally, she highlights fiber as the foundation of it all. Found only in plant foods, it feeds the gut bacteria that produce serotonin and dopamine, key messengers for mood and focus. Most kids, she says, get far too little, missing out on benefits that can help both behavior today and health tomorrow.
Neurodivergence and long-term disease risk
People with autism and ADHD, Lawrence says, tend to have three common underlying issues – higher oxidative stress, more inflammation, and gut dysbiosis or gut dysfunction. “These are risk factors already for our chronic diseases,” she explains.
Studies show that people with ADHD and autism have a dramatically higher risk of cardiovascular disease and diabetes. Many children with ADHD already have abnormal cholesterol levels, yet aren’t being routinely tested. Lawrence says she has spoken with mothers of kids with ADHD who had no idea their child faced a “higher risk of heart disease.” She calls it a major disconnect between pediatric care and cardiology.
So while berries, leafy greens, and fiber might first be used to calm stimming or improve homework time, they also serve a second purpose: protecting neurodivergent kids from heart disease and diabetes later in life. “I want him to live longer and not suffer from these chronic diseases,” she says of her son.
The 3:30 smoothie, soups, and kid-friendly snacks
All of this only matters if kids will actually eat the food. Lawrence knows many neurodivergent children face texture sensitivities and narrow preferences.
Her solution is routine and stealth nutrition. Every afternoon at 3:30, they have a smoothie, a non-negotiable anchor he both expects and appreciates. It blends berries for antioxidants and vitamin C; leafy greens for folate, magnesium, vitamin K, calcium, and fiber; flax seeds, chia seeds, and hemp hearts for plant omega-3s; microalgae oil for EPA and DHA; and sometimes a pea-based vanilla protein powder for texture.
Her son notices the difference. He says he can focus better after the smoothie and prefers homework about half an hour later. Missing smoothie time while traveling affects him. As a child with autism, ADHD, and OCD, he thrives on routine, writes daily schedules, and needs advance warnings of changes. Consistent food routines give him safety and stability.
Beyond smoothies, Lawrence relies on blended soups since he can’t tolerate chunky textures. She purees mushrooms, onions, sweet potatoes, carrots, and beans. “My kid just got tons of mushrooms and onions and sweet potatoes and carrots and beans and everything else I put in that soup,” she says. “He’ll want two or three bowls of soup, and I just consider that such a win.”
She also upgrades treats. A family favorite: pumpkin brownies made with boxed mix plus two-thirds of a can of pumpkin, no eggs or oil. “Now we’ve got all this beta carotene and fiber in his brownies, and he thinks he’s having like this splurge,” she says.
Our bodies don’t lie: nutrition as support, not a cure
If there’s one message Lawrence wants parents to hear, it’s that neurodivergence is not something that needs to be “fixed.” Her goal is not to erase her son’s differences, but to help his brain get what it needs so his strengths can shine.
She has seen firsthand how his body “tells on him” when he eats junk food and how clearly he feels the benefits of nutrient-dense meals. “We are designed to function and thrive on nutrients, and most kids are not getting them,” she says. “When he does get those nutrients, then he is able to be his best self.”
For her, food is both practical and deeply hopeful: a way to support self-regulation and focus today, reduce the risk of chronic disease tomorrow, and help neurodivergent kids grow up with more self-awareness and less shame than previous generations.
“I just think this is such an important conversation,” she says. “This is not something that needs to be cured. It’s not about curing, but thriving.”
For more plant-based health videos, visit the PCRM YouTube channel.
Read more: 12 Vegan Family Dinner Ideas
