Some people have turned vegetarian, vegan or gluten-free for health reasons, but substituted foods for other foods with additives that may come with their own health risks.
Methyl cellulose is in gluten-free bread and in most fake meat products.
Some emulsifiers are found in mayo, other sauces and "ice cream". Not just vegan brands, but overall.
Ethic is the leading reason for the vegan lifestyle [0]. It's also well known [1] that a plant-based diet is effective with colorectal cancer (+9%):
> The random-effects model demonstrated a significant inverse association between plant-based dietary patterns and CRC risk (hazard ratio [HR], 0.91 [95% CI, 0.85–0.97])
But as you guessed it varies between healthy and un-heatly diets:
> This protective association was strengthened when the definition of plant based patterns specifically emphasized the inclusion of healthy plant foods
However those un-healty foods are not restricted to plant-based meal (evidence: any supermarket shelf or snack restaurant), and lentils, tofu or seeds are as much -or more- likely to be found in a long term vegan dish than an impossible burger. As you noted it's "Not just vegan brands, but overall". For the mayo I recommend tahini instead (way more tasty) or just olive oil but if you really need it:
- ~2/3 sunflower oil
- ~1/3 soy milk (with no additive ;-) )
- a bit of citrus juice
- a pinch of salt
-> Blend high speed to emulsify
-> For a thicker texture you may use some silken tofu
Methyl cellulose is in gluten-free bread and in most fake meat products.
Some emulsifiers are found in mayo, other sauces and "ice cream". Not just vegan brands, but overall.