In the twentieth century Australia was dominant in swimming at international events. This was largely due to the high consumption of meat in the diet of Australians. As time went by other nations noticed this and their athletes ate more meat. Today, Even small island nations have access to reasonably priced beef, pork, lamb and poultry. Consequently, Australia's dominance has waned.
Despite consuming a lot of meat, Australians did not die at a young age. Indeed, longevity was extended. New research points to an increase in heart disease, obesity, cancer and diabetes that do tend to shorten life. An example was given of Hawaii where these diseases are rapidly increasing. Red meat is seen as the major cause.
This research has flaws. Higher red meat consumption cannot be directly linked to more "modern" maladies. It could be coincidence. No tests were done on the rising consumption of refined carbohydrates. The call for more vegetables in the diet will improve the situation, but only if less red meat and refined carbohydrates are consumed.
There is an indirect link between red meat consumption and more disease. The feeding of antibiotics to animals to improve body weight has impacted on humans. Antibiotics are not so effective in people generally. Some countries have banned this practice, but all nations need to do so. Overall, there is no evidence of antibiotics in animal feed leading to modern diseases. Control of infections is the biggest problem.