According to the question if
Vegetarians are 'less healthy and have a lower quality of life than meat-eaters'
I'll just leave here the reports of experts from the International Agency for Research on Cancer (IARC), operating at the WHO, from 2015 and 2018 (after verification of over 800 tests over the last two decades), who clearly indicate that:
intake of 50g of processed meat and read mead a day can be linked with
cancer development (processed ie through salting, curing,
fermentation, smoking or other processes that improve taste and
support maintenance) increases the risk of cancer development by as
much as 18%.
American Dietetic Association and Dietitians of Canada about vegetarian diets (older one:from 2003), points out:
Well-planned vegan and other types of vegetarian diets are appropriate
for all stages of the life-cycle including during pregnancy,
lactation, infancy, childhood, and adolescence. Vegetarian diets offer
a number of nutritional benefits including lower levels of saturated
fat, cholesterol, and animal protein as well as higher levels of
carbohydrates, fibre, magnesium, potassium, folate, antioxidants such
as vitamins C and E, and phytochemicals. Vegetarians have been
reported to have lower body mass indices than non-vegetarians, as well
as lower rates of death from ischemic heart disease, lower blood
cholesterol levels, lower blood pressure, and lower rates of
hypertension, type 2 diabetes, and prostate and colon cancer.
So the statement which was closing up the article you mention above (independent.co.uk) says:
There needs to be further study done before this question can be
Thinking about cancer, I find the research of IARC as an answer.