Dietitian Lucy Upton on the real impact of poor diet – and how to build better habits early

When you’re running on little sleep, managing toddler meltdowns, work deadlines, and endless laundry, thinking about nutrition can feel like just one more thing. But what your child eats in those early years doesn’t just fuel their growth, it helps shape their mood, brain development, and long-term relationship with food.

And yet, the odds are stacked against many families. In fact, nearly 1 in 8 children in the UK aged 4-5 are already obese by the time they start school, and that number keeps growing. With ultra-processed snacks, sugary drinks, and misleading ‘100% organic’ baby food pouches everywhere, it’s no wonder. That’s where Lucy Upton, one of the UK’s top paediatric dietitians, steps in.

In her new book, The Ultimate Guide to Children's Nutrition: How to Nurture Happy, Healthy Eaters in the First Five Years, she cuts through the confusion with a no-nonsense, judgement-free approach that speaks directly to today’s parents.

"Honestly, the parents I’ve worked with over my career so far [inspired this book]… I felt strongly about writing a book that could sit alongside parents during these formative years… trustworthy, empathetic, and grounded in evidence," she tells Mother&Baby.

Why early nutrition really matters

The first five years of life are a whirlwind of growth  and what’s on your child’s plate can shape their:
• Gut, brain and immune health
• Long-term risk for obesity or diabetes
• Eating habits and relationship with food for life

Lucy explains, "The foundations for health, eating habits, and a positive, balanced approach to food can be laid in this early window… Nutrition plays a key role in gut health, brain health, and immune health."

Research from the WHO and UNICEF highlights just how important the first 1000 days are, from pregnancy to your child’s second birthday. This is when the foundation for healthy habits is built, and what they eat now can set the stage for their future health. It’s easy to get overwhelmed by all the advice on ‘perfect’ feeding, but Lucy keeps it simple.

She encourages parents to focus on the basics and tune into their child’s needs. For her, nutrition isn’t about filling a plate, it’s about creating a positive food environment where kids can build a healthy relationship with what they eat.

What most parents get wrong (and why it’s not their fault)

With so much advice flying around online, it’s no wonder parents feel overwhelmed. Lucy points out that many of the myths about feeding can actually make things harder.

“There are so many long-held beliefs that stick – things like ‘food before one is just for fun’ or ‘just let them go hungry, and they’ll eat.’ These sound simple, but don’t always reflect what’s going on developmentally," Lucy says.

One of the biggest misconceptions? Treating children like mini adults when it comes to food.

“Children have unique, evolving nutritional needs. Understanding their development helps reduce stress and helps parents stop blaming themselves when their child pushes back at dinner,” she explains

"Take the myth ‘food before one is just for fun,’ for example. While the first foods are great for introducing textures and flavours, they also play a big part in setting up a foundation for good nutrition. By the time they’re 12 months old, children need proper nutrients for growth, and snacks just won’t cut it."

Fussy eating: Why it happens and what actually helps

Food refusal can be super frustrating and isolating, but it’s actually really common. Studies show up to 25% of kids go through some form of picky or fussy eating.

Lucy’s advice? “Focus on the mealtime environment first, and ease up on the pressure… The more attention you give to a child’s eating habits, the less they’ll eat, and the more pushback you’ll get.”

This isn’t just Lucy’s experience – research backs it up. Studies show that pressuring kids to eat can actually lead to more picky eating later on. Kids who are forced to eat tend to develop negative associations with food and are less likely to try new things.

Lucy’s top tips for fussy eating include:

• Remove pressure, no bribing, pleading or “just one more bite”

• Eat together when possible, modelling matters

• Re-offer rejected foods without fuss

• Keep mealtimes short, calm, and distraction-free

By creating a relaxed and positive food environment, you can help spark curiosity and give your child a sense of control over what they eat. This approach builds trust and reduces mealtime anxiety over time.

Allergies and special diets: Know the signs early

Though food allergies and sensitivities require dedicated attention, Lucy provides essential early advice for parents to recognise symptoms early:

"This book focuses on recognising symptoms of food allergy and intolerance… prevention of food allergy, from allergen introduction to gut health, and specific topics like eczema," she says.

Food allergies affect approximately 7% of children in the UK, with reactions ranging from mild to severe. Early identification and correct management of allergies are crucial to ensure a child's health and wellbeing, as well as to avoid potential risks in their environment. Introducing common allergens like peanuts early on (before 6 months) may reduce the risk of developing an allergy.

For parents struggling with managing food allergies, Lucy recommends keeping a food diary and seeking professional advice to ensure balanced nutrition, especially when eliminating certain food groups.

Behaviour and the bigger picture

Toddlers aren’t being difficult, they’re just developing. From teething to increased independence, mealtime challenges often reflect normal growth.

“Small humans are going through substantial developmental changes all the time… Appetite changes, food refusal, and control-seeking are often part of the toddler years,” Lucy explains.

Understanding this can reduce power struggles and help parents feel more in control, even when their child won’t touch a vegetable. Developmental stages like reduced appetite during growth plateaus or a toddler’s desire for independence in food choices are to be expected.

Parents should lean into these shifts, understanding that their child’s growing autonomy and changing nutritional needs are a natural part of the process.

What Lucy wants every parent to know

More than anything, Lucy hopes to lift the pressure and build parental confidence:

“You don’t have to be a perfect parent… The sweet spot is ‘good enough,” she says.

Lucy adds, “I want parents to feel equipped with accurate information and guidance so they can feel confident about feeding decisions and navigate the often bumpy journey.”

Feeding little ones isn’t always easy and that’s okay. Lucy knows parents aren’t meant to be perfect. With small, realistic goals and a calm, steady approach to mealtimes, her advice helps families build healthy eating habits without the pressure, stress, or guilt.

Takeaway for tired parents

Healthy eating isn’t about getting it everything right, it’s about doing your best, one small step at a time. Whether you're figuring out weaning, dealing with fussy eating, or trying to make sense of food allergies, The Ultimate Guide to Children's Nutrition is the supportive, no-judgment guide every parent needs during those messy, magical early years.

About the author

Anne Lora Scagliusi is a Senior Digital Writer at Mother & Baby. She is a Scotland-based journalist with over a decade of international writing experience, specialising in women’s health, maternal mental health, and wellness. Her work has been featured in Vanity Fair, Marie Claire, and Glamour and has appeared on several Vogue global editions. She is a mum to one very energetic bambino and splits her time between Italy and the UK.