Yes — but only some of them, and the effect is modest rather than curative. Controlled feeding trials show that certain fibre blends measurably cut the number and mass of hairballs a cat passes, while other fibres marketed for the same job do nothing at all.
A hairball, or trichobezoar, is a compacted wad of swallowed fur. Cornell University's Feline Health Center explains that hairballs arise from normal grooming, because backward-slanting papillae on a cat's tongue act like a comb and push indigestible hair down the throat. Diet can change how much of that hair leaves through the gut instead of coming back up.
Table of Contents
- What the feeding trials actually measured
- Why fibre moves fur at all
- Which ingredients hold up and which don't
- The gap between the research and the shelf
- When frequent hairballs are a symptom, not a nuisance
- Setting expectations before you switch
- Frequently Asked Questions
What the feeding trials actually measured
The strongest evidence comes from a 42-day randomised trial in 32 cats comparing a control diet against 10% and 20% sugarcane fibre and 10% cellulose. As sugarcane fibre rose, the number of small and medium hairballs excreted per cat per day fell in a linear pattern (P = 0.004), along with total hairball mass (P < 0.01), in work by Loureiro and colleagues published in the *Journal of Nutritional Science* in September 2014. The size breakdown matters more than the headline.
Large hairballs over 2.1 cm were excreted mainly by the control cats (P = 0.003) and were absent altogether from the high sugarcane fibre group — while the 10% cellulose diet showed no effect on any trait measured. Cellulose is one of the most common fibre sources in commercial dry food. That single contrast is the practical takeaway. "Added fibre" on a label is not a mechanism; the specific fibre decides whether anything happens.
Why fibre moves fur at all
The Loureiro authors proposed that long insoluble fibres increase peristaltic stimulation — the wave-like squeezing that moves gut contents along — and push swallowed hair through the digestive tract before it can gather into a mass. They were explicit that further research is needed to validate that explanation.
So the mechanism is plausible and consistent with the results, not settled. It also predicts the limitation most owners run into: diet changes where the hair goes, not how much hair the cat swallows in the first place.
Which ingredients hold up and which don't
A 12-cat comparison by Donadelli and Aldrich tested beet pulp, Miscanthus grass and cellulose against a control. Most of the fibre sources changed nothing on faecal hair measures; only Miscanthus grass lowered total hair weight and hair clumps per gram of dry faeces (P < 0.05). Beet pulp also produced softer stools and cut crude protein digestibility to 82.1%, against 82.1–85.1% for the other diets. Combinations can succeed where single ingredients fail.
A 2×2 factorial study in 24 adult cats by Miltenburg and colleagues found insoluble fibre alone did nothing (P = 0.59) and a keratinolytic enzyme complex — enzymes that break down keratin, the protein in hair — did nothing alone either (P = 0.36). Together they reduced the total number of hairballs excreted (P = 0.034), though the size distribution was unchanged (P = 0.376). Royal Canin's product pages claim its Hairball Care diet, built on psyllium plus insoluble fibres, reduced hairball formation in participating cats within 14 days and doubled the hair eliminated in faeces. That footnote credits a Royal Canin internal study from 2013 against a control feed, not independent publication.
The gap between the research and the shelf
Martha Cannon's peer-reviewed review in the *Journal of Feline Medicine and Surgery* concluded that although a range of commercial hairball-control diets is sold, there is no objective information in the public domain regarding their efficacy, and that no studies had evaluated the other preventives commonly recommended. The published trials therefore tell you about particular fibres at particular inclusion rates — 20% sugarcane fibre, Miscanthus grass, fibre plus a keratinolytic enzyme.
They do not validate the category. A bag labelled for hairball control may be built on cellulose, which failed outright in the one trial that compared it head-to-head. Reading the ingredient panel is the only way to tell which kind you have bought.
When frequent hairballs are a symptom, not a nuisance
This is the part worth pausing on before changing food. Cannon argued that in most shorthaired cats, frequent hairball vomiting signals underlying chronic disease that causes increased fur ingestion or altered gastrointestinal motility — so a diet switch can mask a condition that needs diagnosis.
Cornell's Feline Health Center also warns that a clump of hair can obstruct the intestinal tract, which is a surgical emergency rather than a feeding problem. Signs that point to a veterinary appointment rather than a new bag of food:.
- Repeated retching that produces nothing
- Hairball vomiting in a shorthaired cat, especially if it is new or increasing
- Loss of appetite, lethargy, or constipation alongside the vomiting
- Over-grooming or bald patches, which raise the amount of fur swallowed
- Any change in stool or weight that arrives with the vomiting
Setting expectations before you switch
Treat a hairball diet as a tool that shifts fur from the stomach to the litter tray, and judge it on the right outcome. In the trials, success looked like fewer and smaller clumps in the faeces — not zero hairballs. Watch stool quality during a switch.
Beet pulp's softer stools and lower protein digestibility in the Donadelli and Aldrich work are a reminder that fibre changes carry trade-offs, and a cat on a therapeutic or weight-controlled diet should change food only with a veterinarian's input. If the vomiting continues after a genuine trial on a diet built from the fibres that performed in testing, the food has answered the question. The remaining cause is the cat, not the kibble, and that is a diagnostic question — the large hairballs that vanished entirely from the 20% sugarcane fibre group in the 2014 trial are the realistic ceiling of what diet alone achieved.
Frequently Asked Questions
How long before a hairball diet shows results?
Royal Canin reports change in participating cats within 14 days for its psyllium-based diet, while the sugarcane fibre trial ran 42 days. Allow several weeks before judging.
Does cellulose in my cat's food help with hairballs?
In the Loureiro trial, a 10% cellulose diet showed no effect on any hairball measure tested. Donadelli and Aldrich also found no benefit from cellulose.
Will diet stop my cat swallowing hair?
No. The proposed mechanism works downstream, moving swallowed hair through the gut. Grooming frequency and coat shedding are unchanged by food.