Gut bacteria matter because we have about 2 billion good and bad bacteria living in our gut. If this number in our gastrointestinal tract becomes unbalanced, our health can suffer. A study, published in the journal Frontiers in Nutrition, on western and Mediterranean-type diets found that eating a plant-based diet enhanced the good bacteria living in the gut by up to 7 per cent as compared to only 0.5 per cent from eating a meat-centric, western diet..The western diet used in the study included pig fat, beef fat, butter, eggs, high-fructose corn syrup and sucrose, while the Mediterranean diet consisted of fish oil, olive oil, fish meal, butter, eggs, black and garbanzo bean flour, wheat flour, vegetable juice, fruit puree and sucrose. The diets had the same number of calories..At the end of 30 months, the researchers analysed the good and bad gut bacteria in both diet groups through faecal samples. The findings indicated that good bacteria, primarily lactobacillus which are mostly probiotic, were much higher in the Mediterranean diet group. Not only was their number substantially high but the gut bacteria diversity was also significantly higher in the Mediterranean diet group than in the western.