Everything you actually need to know, distilled.
Keep your dog lean. A body condition score of 4 to 5. It's the single most well-supported finding in canine nutrition research. Nothing else, no food, no supplement, no diet trend, comes close to the effect size of keeping a dog at a healthy weight.
What To Feed
- A complete, balanced food with an AAFCO Growth statement (puppies) or All Life Stages
- Calcium-to-phosphorus ratio between 1.1:1 and 1.4:1
- Grain-inclusive unless your vet specifically says otherwise
- A brand that employs a board-certified veterinary nutritionist (Royal Canin, Purina Pro Plan, Hill's, Eukanuba, Iams all qualify)
- Measured meals twice daily (puppies 3–4x), never free-feeding
What To Avoid
- Never supplement calcium in puppies under 12 months, period
- Raw diets (pathogen and nutrient-deficiency risk across every major study)
- Foods with peas, lentils, or chickpeas in the top 5–10 ingredients (DCM link)
- Grape, raisin, xylitol, chocolate, onion, garlic, full list below
- “Grain-free” as a default, no benefit, documented risks
- Preventive joint supplements for healthy young dogs (no evidence supports them)
Most supplements aren't supported by the research. Here's what is.
That's the whole thing. Everything else on this page is why. Want to understand the science behind each recommendation? Switch to The Full Essay above. Want to read the studies yourself? Switch to Show Me the Research. Or just bookmark this section and come back to it whenever you need a reminder.
The Research Library
Every study the four chapters draw on, by topic, with the finding in one paragraph and a link to the source.
Each card below expands to show the primary finding, methodology, sample size or dose where relevant, and a link to the paper itself. Grouped by topic. If you want to verify any claim in this essay, this is where to start.
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Frequently Asked Questions
›What should I actually feed my dog? Just tell me the answer.
A WSAVA-compliant brand, Royal Canin, Purina Pro Plan, Hill’s Science Diet, Eukanuba, or Iams are the five most commonly cited. Puppy formula through 12 months for medium breeds. Grain-inclusive. Measured meals. Keep your dog at body condition score 4–5 out of 9. That covers 95% of what matters. Everything else on this page is why.
›Is it safe to give my puppy a calcium supplement for stronger bones?
No. Puppies under six months cannot regulate intestinal calcium absorption. They absorb what you give them, with no feedback to shut the process down (Tryfonidou et al. 2002). Excess calcium causes skeletal malformations, osteochondrosis, hypertrophic osteodystrophy, and contributes to hip dysplasia. A complete puppy food already contains the correct amount. Do not add calcium, bone meal, cottage cheese in bulk, or raw bones. The damage is irreversible.
›Are grain-free diets safer or healthier than grain-inclusive diets?
No, and they may be riskier. The FDA began investigating a link between grain-free diets and dilated cardiomyopathy in 2018. The FDA stopped publishing updates in December 2022 citing insufficient data, but peer-reviewed research through 2024 and 2025 (Owens 2023, Coppinger 2024, the November 2025 Veterinary Sciences narrative review) continues to find cardiac differences in dogs eating high-pulse, legume-rich diets versus traditional ones. The specific concern is peas, lentils, chickpeas, and pea protein in the top 5–10 ingredients. Unless your veterinarian has specifically recommended grain-free for a medical reason, feed grain-inclusive.
›What joint supplements actually work?
For healthy young dogs: keeping them lean has the largest effect of anything studied (Purina study, 57–72% reduction in hip dysplasia, 1.8-year lifespan extension). No supplement comes close. For older dogs or dogs with diagnosed osteoarthritis, the best-supported supplements in peer-reviewed trials are marine omega-3 fatty acids (~100 mg EPA+DHA per kg body weight daily) and cold-processed green-lipped mussel extracts such as PCSO-524/Antinol. Glucosamine and chondroitin, despite being the most widely sold joint supplement, consistently fail to beat placebo in blinded trials. UC-II (undenatured type II collagen) has moderate evidence but is mostly manufacturer-funded. There is essentially no peer-reviewed evidence that supplementing healthy young dogs prevents future joint problems.
›Is raw feeding safe if I get the diet balanced by a professional?
Nutritional balance is only one of two problems. The second is pathogen contamination: FDA Vet-LIRN found Salmonella or Listeria in approximately 20% of commercial raw pet food samples (Nemser 2014), and subsequent European studies have found similar or worse rates. Every major veterinary organization, AVMA, CVMA, WSAVA, AAHA, recommends against raw feeding primarily because of the zoonotic risk to humans in the household. If you want the purported benefits of home-prepared food without the raw risks, the evidence-based alternative is cooked home-prepared diets balanced using BalanceIT.com (University of California-Davis).
›How much should my dog weigh? My dog looks skinny to everyone.
You should be able to feel the ribs easily without pressing, see a defined waist from above, and see an abdominal tuck from the side. That is body condition score 4–5 out of 9, the ideal range. Most people, including most visitors and most neighbors, think this looks too thin because they are used to seeing overweight dogs. 59% of U.S. dogs are overweight or obese. If your dog meets the BCS 4–5 criteria, your dog is not too thin. Trust the science, not the comments.
›Is chicken a common food allergen I should avoid?
True food allergies are rare in dogs, around 0.2% of the population. When they do occur, chicken is third on the list of common allergens (15% of cases) behind beef (34%) and dairy (17%) and ahead of wheat (13%) and lamb (5%), according to Mueller, Olivry & Prélaud’s 2016 systematic review. But because true allergy is uncommon, you should not preemptively avoid chicken unless your dog has a diagnosed allergy confirmed by a veterinarian-supervised elimination diet trial. Blood and saliva tests for food allergies are not reliable.
›When should I switch from puppy food to adult food?
For medium-breed dogs (Lagotto, Cocker Spaniel, Border Collie, similar): transition over two weeks at 12 to 14 months of age. Small breeds transition earlier (10–12 months); large and giant breeds later (18–24 months). Puppy food contains more calories and calibrated calcium/phosphorus for growth; adult food does not. Switching too early can slow growth and create body condition management problems; switching too late can contribute to overweight.
›How many treats can I give per day?
No more than 10% of daily caloric intake, the standard figure from the American Animal Hospital Association. This is more restrictive than most families realize when they actually count. A 30-pound dog eating about 700–800 calories per day has a treat budget of roughly 70–80 calories. Count the training treats, the cheese, the peanut butter, the table scraps. They add up quickly and are the single largest driver of the 59% canine obesity figure.
Questions About Feeding Your Dog?
Nutrition decisions compound over years. If you have a specific question about your own dog, what to feed, when to switch, what supplement to try, how to read a label. I’m happy to answer one. Not a consultation. Not a service. Just a question, answered from eleven years of experience and the peer-reviewed literature this article draws on.
If you’re considering a Lagotto and want to know what we do at Northwest Lagotto, the waitlist and breed pages are the right places to start.
Primary Sources, Quick Reference
- Kealy RD, Olsson SE, Monti KL, et al. Effects of limited food consumption on the incidence of hip dysplasia in growing dogs. JAVMA 1992;201(6):857–863.
- Kealy RD, Lawler DF, Ballam JM, et al. Effects of diet restriction on life span and age-related changes in dogs. JAVMA 2002;220(9):1315–1320.
- Lawler DF, Larson BT, Ballam JM, et al. Diet restriction and ageing in the dog: major observations over two decades. Br J Nutr 2008;99(4):793–805.
- Tryfonidou MA, van den Broek J, van den Brom WE, Hazewinkel HAW. Intestinal calcium absorption in growing dogs is influenced by calcium intake and age but not by growth rate. J Nutr 2002;132:3363–3368.
- Hazewinkel HAW, van den Brom WE, van ’t Klooster AT, et al. Calcium metabolism in Great Dane dogs fed diets with various calcium and phosphorus levels. J Nutr 1991;121(11 Suppl):S99–S106.
- Nap RC, Hazewinkel HAW, Voorhout G, et al. Growth and skeletal development in Great Dane pups fed different levels of protein intake. J Nutr 1991;121(11 Suppl):S107–S113.
- Salt C, Morris PJ, Wilson D, et al. Association between life span and body condition in neutered client-owned dogs. J Vet Intern Med 2019;33(1):89–99.
- Serisier S, Feugier A, Delmotte S, et al. Higher neonatal growth rate and body condition score at 7 months are predictive factors of obesity in adult female Beagle dogs. BMC Vet Res 2013/2017.
- Bray EE, Zheng Z, Tolbert MK, et al. Once-daily feeding is associated with better health in companion dogs. GeroScience 2022;44(3):1779–1790.
- Association for Pet Obesity Prevention. 2024 State of U.S. Pet Obesity Report.
- Roush JK, Cross AR, Renberg WC, et al. Multicenter veterinary practice assessment of the effects of omega-3 fatty acids on osteoarthritis in dogs. JAVMA 2010;236(1):59–66.
- Mehler SJ, May LR, King C, et al. A prospective, randomized, double blind, placebo-controlled evaluation of EPA and DHA on clinical signs in dogs with osteoarthritis. Prostaglandins Leukot Essent Fatty Acids 2016;109:1–7.
- Fritsch DA, Allen TA, Dodd CE, et al. A multicenter study of the effect of dietary supplementation with fish oil omega-3 fatty acids on carprofen dosage in dogs with osteoarthritis. JAVMA 2010;236(5):535–539.
- Kampa N, Kaenkangploo D, Jitpean S, et al. Study of the effectiveness of glucosamine and chondroitin sulfate, marine based fatty acid compounds, and carprofen for hip osteoarthritis. Front Vet Sci 2023;10:1033188.
- Gupta RC, Canerdy TD, Lindley J, et al. Comparative therapeutic efficacy and safety of type-II collagen (UC-II), glucosamine and chondroitin in arthritic dogs. J Anim Physiol Anim Nutr 2012;96(5):770–777.
- Vandeweerd JM, Coisnon C, Clegg P, et al. Systematic review of efficacy of nutraceuticals to alleviate clinical signs of osteoarthritis. J Vet Intern Med 2012;26(3):448–456.
- Freeman LM, Michel KE. Evaluation of raw food diets for dogs. JAVMA 2001;218(5):705–709.
- Nemser SM, Doran T, Grabenstein M, et al. Investigation of Listeria, Salmonella, and toxigenic Escherichia coli in various pet foods. Foodborne Pathog Dis 2014;11(9):706–709.
- Vecchiato CG, Schwaiger K, Biagi G, Dobenecker B. From nutritional adequacy to hygiene quality: a detailed assessment of commercial raw pet-food. Animals 2022;12(18):2395.
- Davies RH, Lawes JR, Wales AD. Raw diets for dogs and cats: a review with particular reference to microbiological hazards. J Small Anim Pract 2019;60(6):329–339.
- Owens EJ, LeBlanc NL, Freeman LM, Scollan KF. Comparison of echocardiographic measurements and cardiac biomarkers in healthy dogs eating nontraditional or traditional diets. J Vet Intern Med 2023.
- Coppinger LM, Freeman LM, Tyrrell WD Jr, et al. Echocardiographic and electrocardiographic findings in Irish Wolfhounds eating high-pulse or low-pulse diets. J Vet Intern Med 2024;38(3):1300–1304.
- Role of Diet as a Predisposing Factor for Dilated Cardiomyopathy in Dogs: A Narrative Review. Veterinary Sciences 2025;12(11):1106.
- Mueller RS, Olivry T, Prélaud P. Critically appraised topic on adverse food reactions of companion animals (2): common food allergen sources in dogs and cats. BMC Vet Res 2016;12:9.
- WSAVA Global Nutrition Committee Guidelines on Selecting Pet Foods. World Small Animal Veterinary Association.
Common Questions
What families ask about feeding
What is the single most important thing I can do for my dog's nutrition and long-term health?
Keep your dog lean - a body condition score of 4 to 5 on a 9-point scale. This is the single most well-supported finding in all of canine nutrition research. The 14-year Purina Life Span Study (Kealy et al., 1992, 2002; Lawler et al., 2008) followed 48 Labrador Retrievers and found that dogs fed 25% less than their littermates had 57 to 72% less hip dysplasia at age 2, developed osteoarthritis 1.5 years later on average, and lived 1.8 years (16%) longer. No supplement, diet, or intervention in the peer-reviewed literature comes close to the effect size of simply keeping a dog lean.
Should I supplement my puppy's diet with calcium for stronger bones?
No. Never. Puppies under 6 months cannot regulate intestinal calcium absorption. Research by Tryfonidou et al. (2002, Journal of Nutrition) showed that passive calcium absorption accounts for approximately 53% of dietary calcium in growing dogs and cannot be downregulated. If you feed excess calcium, the puppy absorbs it whether it needs it or not. Excess calcium during growth causes hip dysplasia, osteochondritis dissecans, hypertrophic osteodystrophy, and other developmental orthopedic disease. A complete and balanced puppy food already contains the correct calcium level. Do not add calcium, bone meal, cottage cheese, or raw bones to a growing puppy’s diet.
What joint supplements actually work, based on peer-reviewed evidence?
Ranked by strength of peer-reviewed evidence: (1) Weight management - the largest effect size of anything ever studied for canine joints. (2) Marine-source omega-3 fatty acids (EPA and DHA) at approximately 100 mg per kg body weight per day - best-studied joint supplement in dogs, with multiple large multi-site trials. (3) Cold-processed green-lipped mussel lipid extract, specifically PCSO-524 (Antinol), which matched carprofen for pain reduction in Kampa et al. 2023. (4) Undenatured type II collagen (UC-II) has moderate evidence but mostly manufacturer-funded. Glucosamine and chondroitin consistently fail to beat placebo on objective measures. There is essentially no peer-reviewed evidence that supplementing healthy young dogs prevents future joint problems.
Is raw feeding safe for my dog?
Every major veterinary organization - AVMA, CVMA, WSAVA, AAHA, CDC, and FDA - recommends against feeding raw meat-based diets to companion animals. The FDA Veterinary Laboratory Investigation and Response Network found that approximately 20% of commercial raw pet food samples tested positive for Salmonella or Listeria monocytogenes, compared with roughly 0.1% of dry foods (Nemser et al., 2014). A 2022 German study found that every single raw meat-based diet tested had at least one nutritional concern, and 96% failed hygiene standards. Raw feeding also poses documented zoonotic transmission risks to humans in the household.
Is grain-free food bad for dogs?
The concern is specifically with diets containing high proportions of legumes (peas, lentils, chickpeas) as primary ingredients, not grain-free per se. The FDA began investigating a link to canine dilated cardiomyopathy in 2018 and paused public updates in December 2022. Peer-reviewed research from 2023 to 2025 has continued to find cardiac effects in dogs on high-pulse diets (Owens et al. 2023, Coppinger et al. 2024). The practical recommendation: feed grain-inclusive unless your veterinarian specifically directs otherwise, and avoid any diet where peas, lentils, chickpeas, or pea/legume protein appear in the top 5 to 10 ingredients.
How many times a day should I feed my dog?
Puppies need multiple meals daily: 3 to 4 meals until 12 weeks, 3 meals from 3 to 6 months, and 2 meals from 6 months onward. For adult dogs, twice daily is a reasonable default. A 2022 Dog Aging Project analysis (Bray et al., GeroScience) of over 24,000 companion dogs found that adult dogs fed once daily had lower odds of several disease categories, but this study is cross-sectional and correlational, not causal. Puppies should never be fed once daily regardless. For adult dogs, twice daily remains a reasonable default.
What dog food should I feed my Lagotto Romagnolo?
Northwest Lagotto feeds Royal Canin Medium Puppy through 12 months and Royal Canin Medium Adult thereafter. Other foods meeting the same WSAVA standards are also reasonable: Purina Pro Plan, Hill’s Science Diet, Eukanuba, Iams. What matters more than brand is that whatever you feed meets three non-negotiable criteria: AAFCO Growth statement, calcium-to-phosphorus ratio between 1.1:1 and 1.4:1, and grain-inclusive formulation.
What are the most common food allergens in dogs?
According to a 2016 systematic review by Mueller, Olivry, and Prélaud in BMC Veterinary Research analyzing 297 dogs across multiple studies, the most common canine food allergens are beef (34% of cases), dairy products (17%), chicken (15%), wheat (13%), and lamb (5%). Grain is well down the list - the marketing framing of grain-free diets as hypoallergenic is not well supported. True food allergies affect only about 0.2% of dogs overall. Proper diagnosis requires a strict veterinary-supervised elimination diet trial, not a blood or saliva test.