Nutrition for healthspan.

Food is information. Every meal is a set of signals to the metabolic, immune and microbiome systems. The right signals — repeated, daily, over years — compound into healthspan. The wrong ones compound the other direction.

Three biological functions food serves, in order of underrated-ness:

1. Substrate — providing the raw materials (amino acids, fatty acids, minerals, vitamins) the body uses for repair and renewal.
2. Signaling — every macronutrient triggers hormonal, inflammatory and gene-expression responses. Insulin/IGF-1 from carbs; mTOR from leucine; PPAR from fats; satiety hormones from fiber. The signaling effect of a meal often exceeds the substrate effect.
3. Microbiome modulation — fiber, polyphenols and prebiotic compounds shape which bacteria thrive in the gut. The gut microbiome influences immune function, mood, joint health and aging trajectory more than was understood even five years ago.

The mainstream pet-food paradigm is built almost entirely around macro #1 — calories, protein percentage, "complete and balanced." That isn't wrong. It's just one-third of the picture.

"Most premium pet food is built to keep an animal alive. We want food built to keep an animal thriving."

Most premium-positioned commercial pet foods exploit five marketing patterns that don't translate to actual nutritional quality:

• "Grain-free" — neutral or slightly negative. The 2018 FDA investigation linked some grain-free diets to dilated cardiomyopathy in dogs. Grain-free isn't intrinsically better.
• "Real meat first" — meaningful only if real meat appears multiple times in the first five ingredients. Single mention often = small percentage of formula.
• "Human-grade" — useful but vague. Less meaningful than "AAFCO complete" verification.
• "Holistic" — no regulatory definition. Marketing word.
• "Limited ingredient" — useful only for animals with confirmed allergies. Otherwise just narrows nutritional diversity unnecessarily.

What to actually look for, on any label:

1. Named animal proteins — "chicken meal" and "salmon" beat "poultry by-product" or "meat meal." Specificity matters.
2. Whole-food micronutrient sources — "blueberries, kale, sweet potato" beat "vitamin pre-mix #4."
3. Stated Ω-3 source — fish oil, krill, flax. EPA + DHA quantified per kg if possible.
4. Modest carbohydrate — for dogs and especially cats, lower-carb formulations are typically better. Not zero-carb (fiber matters), but not 50%+ either.
5. Manufacturing transparency — country of origin, third-party testing, lot batch consistency. Premium brands publish this; mass-market brands don't.

Dogs · facultative omnivores

Dogs evolved alongside humans for ~30,000 years and developed extra copies of the AMY2B gene that allow them to digest starch — a clear divergence from wolves. They thrive on a wide range of macro ratios: 25–40% protein on a dry-matter basis, 15–35% fat, 25–50% carbohydrate. Working dogs and seniors typically benefit from the upper protein range; sedentary urban dogs from the moderate range.

Cats · obligate carnivores

Cats are physiologically obligate carnivores — they require dietary taurine, can't efficiently synthesize vitamin A from carotenoids, and have very limited carbohydrate-handling capacity. Target macros: 40–55% protein, 30–45% fat, <15% carbohydrate. The biggest single nutrition mistake in cats is feeding them a dog-style high-carb dry kibble for their entire life. Wet food once daily — at minimum — meaningfully changes the trajectory.

Horses · hindgut fermenters

Horses are evolved for continuous grazing of forage. Their digestive system depends on near-constant fiber flow through the hindgut. The single most important nutrition lever in horse healthspan: forage first, always. Concentrates (grain, sweet feed, processed pellets) should be the smallest portion of intake by volume, not the largest. Sport horses need calories from concentrates; the answer is more forage plus targeted concentrate, not less forage and more concentrate.

The single most actionable nutrition lever for healthspan in any species is the Ω-6 to Ω-3 fatty acid ratio. Wild prey-based diets sit around 4:1. Most commercial pet kibble runs 8:1 to 20:1 — a significant chronic inflammatory signal that erodes joints, vasculature, kidneys and brain over years.

The fix is among the simplest interventions in pet nutrition: add an EPA + DHA supplement (fish oil, krill oil, or algal oil for vegetarian preference) at 50–100 mg combined per kg body weight daily. Research-grade evidence for inflammation reduction; modest cost; minimal downside; species-appropriate for dogs, cats and horses.

What we covered in our joint article at the joint level is the same mechanism playing out across every system — gentle every-day-for-years compounds.

When you feed matters almost as much as what you feed. The metabolic literature in humans is now clear that compressing the daily eating window has independent benefits beyond calorie count. The same physiology applies — with species-appropriate caveats — to pets.

Dogs: two meals per day, ~10 hours apart, with a 14-hour overnight fast, suits most adults. Don't impose extended fasts on young, small, or high-metabolic-rate dogs.

Cats: more controversial. The "cats need to graze constantly" myth is widespread but evidence-thin. 2–3 distinct meals per day with no constant kibble bowl appears to work well for most adult cats — and dramatically helps weight control. Insulin spikes from constant grazing on dry kibble drive significant feline metabolic dysfunction.

Horses: opposite pattern. Continuous low-rate forage access through the day matches their evolutionary digestive design. Long gaps without forage are stressful and increase ulcer risk. The "two big meals" pattern is wrong for horses.

1. What are the three functions food serves beyond calorie provision?
2. Looking at your animal's current food label — what's the first named protein source, and how many times does it appear in the first five ingredients?
3. What's your animal's current Ω-6:Ω-3 ratio, approximately? (If you don't know, that's a finding.)
4. What's your current feeding rhythm? Could you compress, distribute or otherwise improve it for the species?
5. If you changed exactly one nutrition variable in the next 30 days, what would it be — and what's the smallest version of that change you could test?