Veganism is expensive
The cheapest foods in most markets are plant staples: rice, pulses, oats, seasonal vegetables. Modelling across high-income countries puts plant-based diets among the least costly.
When people actually try to go vegan, their grocery bills go up: the plant-based milks, cheeses, burgers and ready meals that make the switch livable cost far more than the animal products they replace. Telling a family to live on dried beans and rice ignores that this is not how most people cook or eat, and that the hours of soaking, planning and cooking it takes, plus the kitchen and the shops it depends on, are costs that fall hardest on people who are already short of money and time. For many households, eating vegan in a way they can sustain is simply something they cannot afford.
Comparative modelling of diet costs in high-income countries has found vegan patterns to be among the cheapest of those assessed, principally because pulses and grains are inexpensive sources of protein and calories relative to meat.
The perception comes from the shelf where the meat substitutes are. Those products are priced as convenience goods and are genuinely expensive, and they are optional. A diet of dried lentils, rice, oats, frozen vegetables, peanut butter and seasonal produce is cheaper than most omnivorous equivalents. The real constraints are time, cooking facilities and access, which are serious for some households and are not the same thing as the food costing more.
Presenting only the evidence that supports a conclusion while leaving out evidence that tells against it.
How it applies here: Prices the diet from meat substitutes and speciality products rather than from the staples that make up most of what is actually eaten.
Composition: assuming what is true of the parts must be true of the whole. Division: assuming what is true of the whole must be true of each part.
How it applies here: Infers the cost of the whole diet from its most expensive components, which are also its most optional ones.