Animal advocates speak of reducing harm. The industry speaks of shifting consumption. Policymakers talk about lowering carbon footprints. All of these framings hide the real stakes: the number of living beings killed. And in that cold arithmetic, size matters.
The “small body problem” is simple but devastating. Replace one cow with hundreds of chickens or thousands of fishes, and the death toll multiplies. Campaigns that encourage people to “cut down on red meat” while leaving the door wide open to “white meat” are not progress at all, they are a massacre in disguise.
Faunalytics, together with Bryant Research, attempted to measure just how widespread this problem is by analysing interventions aimed at reducing or eliminating animal product use. The results are sobering.
Meta-analysis looked at:
▫️306 studies screened → narrowed down to 38 relevant studies.
▫️ These studies contained 78 interventions targeting large-bodied animals (like cows and pigs) and 64 interventions that allowed data on small-bodied animals (like chickens and fishes).
▫️Researchers asked: when people are encouraged to cut animal products, do they quietly substitute smaller bodies for larger ones?
The answer is not as neat as campaigners might hope.
Key Findings
1. No overall proof of the small body problem. Across all studies, there was no consistent increase in consumption of chickens or fishes when people reduced cow or pig flesh. That may sound reassuring, but it comes with a huge caveat.
2. The data is messy. Studies were all over the place in design, measurement, and outcome. Some interventions did trigger substitution toward small-bodied animals, others showed reductions, and when all results were averaged out, they cancelled each other. A statistical stalemate doesn’t mean the problem isn’t real. It means it’s unpredictable, which is worse.
3. Reductionism is ineffective. On the whole, interventions didn’t reliably reduce animal consumption at all. Some worked, some backfired. Advocates can’t lean on reduction messaging and expect consistent results.
4. One strategy showed promise: choice architecture. Subtle but structural changes, default plant-based menu options, supermarket layouts that pair animal products with alternatives, nudges that make vegan options the easiest, consistently steered people away from small-bodied animal use. Importantly, these didn’t trigger the substitution trap.
Why This Matters
Think about it:
One cow ≈ 200 chickens.
One pig ≈ 100 fishes.
A campaign that convinces someone to swap cows for chickens has not “saved animals.” It has cost hundreds more lives. The industry knows this. That’s why they push chickens and fish as “lean,” “healthy,” and “sustainable” substitutes. It’s not a health campaign, it’s a numbers game where smaller bodies mean larger profits and more lives destroyed. Veganism cannot be reduced to personal health or climate metrics. Those framings lead people straight into the small body problem. What looks like progress, swapping beef for chicken, is actually mass killing on a far greater scale. Justice for animals means ending their commodification entirely, not swapping one injustice for another.
The Trap of Environmental and Health Appeals
Most mainstream appeals ask people to cut out “red meat” to protect their arteries or reduce their carbon footprint. But if people turn to chickens or fishes instead, the result is a bloodbath hidden behind lower greenhouse gas numbers. Justice cannot be measured in kilograms of CO₂ or cholesterol levels alone. It must be measured in lives spared.
What Advocates Should Do
▫️Reject reductionist framings. Messaging like “Meatless Monday” or “cut down on red meat” risks feeding the small body problem.
▫️Push plant-based, not substitution. The only safe shift is away from animal products altogether.
▫️Use choice architecture. Defaults and nudges work better than moral appeals alone, and they avoid pushing people toward smaller animals.
▫️Demand more research. The lack of data is itself alarming. Advocates should not accept ignorance as safety.
The Bigger Picture
The small body problem reveals something uncomfortable: even when people “change,” they may not change in ways that matter for animals. This should be a wake-up call to the movement.
If our strategies allow for the possibility that billions more chickens and fishes are killed in the name of “progress,” then we are not dismantling animal exploitation, we are rearranging its victims.
This is why veganism cannot be reduced to incrementalist nudges or consumer swaps framed only around health and climate. It is a justice movement. It demands we stop treating animals as property and resources to be shuffled around on a ledger.
The Faunalytics meta-analysis did not find overwhelming evidence of the small body problem. But that is not a green light for complacency. The variability, the mixed outcomes, and the very real examples of backfiring interventions show the risk is real.
The lesson is clear: reductionism is not enough. Justice cannot be won by trading large bodies for small ones. The only way out of the numbers game is to step outside of it, to stop using animals altogether.
Until then, the arithmetic of suffering continues, and every substitution campaign risks adding zeros to the death toll.