The nutrient density of meat explains why carnivore has become a popular movement in recent times. Coupled with this is the fact that the positive health arguments for high fruit and vegetable consumption are largely based on observational studies. However, clinical trials have not been as convincing. For example:
One study looked at the effect of 600g fruit and veg daily intake on oxidative DNA damage and repair in healthy subjects. Subjects were randomised into three groups receiving an antioxidant-free basal diet and 600 g of fruits and vegetables, or a supplement containing the corresponding amounts of vitamins and minerals, or placebo. The results showed no difference between any of the groups. The authors concluded: ‘This suggests that the inherent antioxidant defence mechanisms are sufficient to protect circulating mononuclear blood cells from reactive oxygen species.’ (emphasis mine)
Ref: No Effect of 600 Grams Fruit and Vegetables Per Day on Oxidative DNA Damage and Repair in Healthy Nonsmokers (Moller et al 2003)
In another study, looking at high (4200g) versus low (800g) per week vegetable consumption on clinical, immunological and antioxidant markers, there was again no difference between both groups after 4 weeks.
Ref: Effects of High Consumption of Vegetables on Clinical, Immunological, and Antioxidant Markers in Subjects at Risk of Cardiovascular Diseases; Peluso et al (2018)
One study even showed an inverse relationship between fruit/veg consumption and oxidative stress. It involved a 10-week absence of fruit and veg in order to test the antioxidant effect of green tea. It transpired there was only a transient effect on antioxidant markers from the green tea yet subjects showed improved markers after the complete depletion of fruit and veg. The authors concluded: ‘The overall effect of the 10-week period without dietary fruits and vegetables was a decrease in oxidative damage to DNA, blood proteins, and plasma lipids, concomitantly with marked changes in antioxidative defence.’
Ref: Green tea extract only affects markers of oxidative status postprandially: lasting antioxidant effect of flavonoid-free diet; Young et al (2007)