5 Common Mistakes Puppy Owners Make (and How to Give Your Dog the Healthiest Start in Life)
Learn the 5 biggest mistakes puppy owners make with diet and health — from overfeeding to supplements — and how to help your dog grow strong and balanced.
Introduction
Bringing home a new puppy is one of life’s greatest joys — that wagging tail, those oversized paws, and the irresistible smell of “puppy breath.” But amid the cuddles and chaos, one thing often gets overlooked: long-term health starts from day one.
As a canine nutritionist, I see the same health and nutrition mistakes crop up again and again. Many of them are made with the best of intentions — owners simply want to do what’s right. Unfortunately, misinformation online, poor labelling, and social media “advice” can easily derail even the most devoted dog parent.
This article explores five of the most common mistakes owners make with their puppy’s health, backed by science and practical solutions to help you raise a thriving, well-balanced dog.
1.) Feeding the Wrong Type of Food for Growth
One of the biggest misconceptions I see is that all puppy foods are created equal. In truth, puppies — especially large or giant breeds — have very specific nutritional needs to support steady growth, proper skeletal development, and a balanced body composition.
Why Puppy Nutrition Matters
Puppies have higher energy and nutrient demands than adult dogs due to rapid tissue growth and organ development. The first 12–18 months (up to 24 months in giant breeds) are critical for bone mineralisation, muscle mass formation, and immune function.
A correctly balanced puppy diet must provide:
High-quality, digestible protein for lean muscle
Controlled calcium and phosphorus ratios for skeletal development
Essential fatty acids (especially DHA) for brain and eye health
Micronutrients like zinc, selenium, and copper in precise amounts
Common Owner Mistakes
Many owners choose a food labelled simply “puppy” or “for all life stages,” assuming it’s sufficient. However, only foods that meet FEDIAF (Europe) or AAFCO (US) growth standards — and specifically those formulated for large-breed growth — guarantee safe nutrient levels.
Large-breed puppies are especially vulnerable to developmental orthopaedic diseases (DOD) such as hip dysplasia, osteochondrosis, or panosteitis when fed diets too rich in energy or calcium.
In other words: more nutrients don’t equal healthier growth — they equal faster growth, and that can be harmful.
Expert Tip
Check the packaging for statements such as:
“Formulated to meet the nutritional levels established by FEDIAF for growth, including large size dogs.”
If your puppy is a toy breed, ensure their diet has adequate calorie density — they have smaller stomachs and higher metabolic rates, meaning they need small, frequent meals to avoid hypoglycaemia.
Transitioning from puppy to adult food should occur only once skeletal maturity is reached (typically 12 months for small breeds, up to 24 months for giant breeds).
2.) Overfeeding or Free-Feeding
Few things make new puppy owners happier than seeing an empty bowl — it feels like love well received. But overfeeding is one of the most damaging habits you can start.
Why Overfeeding Is a Problem
Excess calories lead to rapid weight gain, which can predispose your dog to:
Joint and skeletal problems during growth
Metabolic disorders later in life
Reduced lifespan and mobility
Studies have shown that dogs fed restricted energy diets during growth had significantly lower risk of developing hip dysplasia and lived up to 1.8 years longer (Kealy et al., 2002).
Free-Feeding Risks
Leaving food available all day (known as “free-feeding”) removes the owner’s ability to monitor appetite and digestion. It also promotes constant insulin release, which can lead to metabolic imbalances and obesity.
Expert Feeding Guidance
Feed measured meals 3–4 times daily until 6 months, then reduce to 2 meals.
Calculate feeding amounts based on expected adult weight, not current weight.
Monitor your puppy’s Body Condition Score (BCS) weekly — you should feel ribs easily but not see them.
Consider completing a growth chart for your puppy from The Waltham Growth Charts
If in doubt, your canine nutritionist can help you calculate Resting Energy Requirements (RER) and adjust based on activity and body condition.
Did you know? Most puppy feeding guides on packaging are based on lab averages and often overestimate calorie needs by 15–25%.
3.) Adding Too Many Supplements and Toppers
In the age of social media, supplements are everywhere — from fish oils to probiotics to powdered “superfoods.” While many have legitimate uses, adding them to a complete and balanced puppy diet can easily unbalance nutrient ratios.
Why This Matters
Excess or poorly balanced supplementation can cause harm:
Too much calcium or vitamin D → abnormal bone growth, joint deformities
Too much fish oil → digestive upset, diarrhoea, imbalance in omega-6:omega-3 ratio
Random multivitamins → vitamin A or D toxicity
If your puppy’s base diet already meets FEDIAF or AAFCO growth guidelines, it does not require additional supplementation unless under veterinary or nutritionist advice.
When Supplements Can Help
Certain cases benefit from targeted use:
Joint support in predisposed breeds
Probiotics/prebiotics after antibiotics or digestive upset
Omega-3 (EPA/DHA) in skin-sensitive breeds — but always dose precisely
Remember: supplements are not a shortcut to good nutrition — they’re a tool to fill gaps, not create them.
4.) Rushing Dietary Changes or “Tasting” Too Many Foods
Puppies can be fussy eaters — and many owners respond by switching foods too quickly. However, frequent diet changes disrupt the delicate gut microbiome responsible for digestion and immune development.
The Gut Microbiome in Puppies
A puppy’s intestinal bacteria are still developing during the first 6–12 months. Every sudden dietary shift changes the microbial population, which can trigger:
Loose stools or diarrhoea
Flatulence and bloating
Food aversions due to discomfort
Common Owner Mistake
Changing brands weekly to “find what they like,” or introducing new proteins without transition, can lead to chronic digestive upset that’s mistaken for food allergies.
The Right Way to Transition
When changing foods, do so gradually over 7–10 days - 124 days if stomach issues are present
Mix 25% new food with 75% old for 2–3 days
Move to 50/50 for 2–3 days
Increase to 75% new, 25% old
Finally, 100% new food
During this time, avoid extra toppers or treats — allow the gut to adjust. If diarrhoea persists, consult your vet or canine nutritionist before changing again.
Expert Tip
Fussiness is often behavioural, not nutritional. Puppies quickly learn that refusing food brings attention or alternatives. Consistency in feeding time and environment helps reinforce good eating habits.
5.) Ignoring Gut Health and Parasite Management
A puppy’s immune and digestive health are intimately linked — nearly 70% of the immune system resides in the gut. Neglecting gut balance or parasite control can have far-reaching effects on development and wellbeing.
Gut Health 101
Puppies’ immune systems rely on a balanced gut microbiome to distinguish between “safe” and “harmful” stimuli. Poor diet, stress, antibiotics, or infection can all disrupt this balance (dysbiosis).
Symptoms of imbalance include:
Intermittent soft stools
Bloating or excessive gas
Frequent grass eating
Skin or ear issues
Parasite Control
Worms (roundworm, hookworm, tapeworm) can cause anaemia, poor growth, dull coats, and nutrient loss. Yet many owners forget or delay worming after the initial breeder/vet schedule.
Best Practice
Worm every 2 weeks until 12 weeks old, then monthly until 6 months, then every 3 months (or as advised by your vet).
Choose veterinary-recommended wormers rather than pet shop versions — they’re more effective and safer for young immune systems.
If your puppy experiences chronic tummy upset, a faecal test (worm egg count) can help rule out hidden infections like Giardia.
Probiotics: Consider adding a vet-approved probiotic (like Purina Fortiflora or Protexin) after worming or antibiotics to help restore gut flora.
Bonus: Over-Sanitising the Environment
In our efforts to keep puppies safe, we sometimes overdo hygiene. Constant disinfecting or use of chemical sprays can reduce exposure to natural microbes that train the immune system.
Puppies need controlled, healthy exposure — think clean, not sterile.
Outdoor exploration, soil contact, and social interaction with vaccinated dogs help develop a resilient immune system.
Creating a Strong Foundation for Life
The first year of a dog’s life sets the tone for their entire adulthood. Nutrient imbalances, overfeeding, and gut disruption in early months can have lifelong consequences — from allergies to joint disease.
Here’s how to give your puppy the healthiest possible start:
My Puppy Health Checklist
Choose a growth-appropriate food meeting FEDIAF or AAFCO standards
Feed measured meals, not free access
Avoid random supplements — seek professional guidance
Transition foods slowly, giving the gut time to adapt
Maintain consistent worming and vaccination schedules
Keep the environment clean but not sterile
Monitor growth rate weekly and adjust portions by body condition
Seek help early if stools remain soft, appetite fluctuates, or your pup seems “off”
Common Myths to Stop Believing
“More protein makes them grow faster.”
Excess energy, not protein, drives rapid (and unhealthy) growth.
“Natural diets don’t need balancing.”
Even fresh or raw diets must be formulated to FEDIAF standards — puppies are especially vulnerable to imbalances.
“They’ll grow out of soft stools.”
Persistent loose stools can indicate poor diet choice, parasites, or gut dysbiosis.
Want Expert Puppy Guidance?
If you’re unsure whether your puppy’s diet is truly balanced, you’re not alone. Most commercial foods, supplements, and online advice can be confusing — but getting it right early prevents years of health struggles later.
You can:
Book a Puppy Nutrition Consultation with The Canine Dietitian for tailored guidance.
Explore e-books and resources here.
References
Kealy, R.D., et al. (2002). Effects of diet restriction on life span and age-related changes in dogs. Journal of the American Veterinary Medical Association, 220(9), 1315–1320.
FEDIAF Nutritional Guidelines (2021). Nutritional Guidelines for Complete and Complementary Pet Food for Cats and Dogs.
National Research Council (2006). Nutrient Requirements of Dogs and Cats. The National Academies Press.
Case, L.P., Daristotle, L., Hayek, M.G., & Raasch, M.F. (2011). Canine and Feline Nutrition: A Resource for Companion Animal Professionals. 3rd ed. Elsevier.
Zaine, L., et al. (2018). Influence of energy and calcium on bone development in growing dogs. Journal of Animal Physiology and Animal Nutrition, 102(4), e372–e382.
Bosch, G., Hagen-Plantinga, E.A., & Hendriks, W.H. (2015). Dietary nutrient profiles of commercial dog foods compared with NRC and FEDIAF recommendations. British Journal of Nutrition, 113(9), 1520–1531.
Schmitz, S., Suchodolski, J. (2016). Understanding the canine intestinal microbiota and its modification by pro-, pre- and synbiotics – what is the evidence? Veterinary Medicine and Science, 2(2), 71–94.
Final Thoughts from The Canine Dietitian
Raising a puppy isn’t about perfection — it’s about consistency and awareness. A few mindful choices in these early months make a world of difference later on. Nutrition is the foundation of lifelong health, and as I often say:
