The diet is assumed to contribute to many of our present non-communicable diseases. Vegetarian products are instead considered to be health promoting, However, it is not verified that the modern vegetarian and vegan products are healthier than the ones they are meant to replace. Products based on vegetables are nowadays often produced with advanced techniques and can therefore differ substantially from the original vegetables. The epithelium in the gut is protected by a mucus layer that efficiently prevents bacteria to encounter the epithelium and even to translocate into the gut and the blood stream. In several inflammatory conditions such as e.g., inflammatory bowel disease (IBD) the barrier integrity is disrupted, and translocation will occur. Fibers are important for the gut microbiota enabling the production of short chain fatty acids (SCFA) that is necessary as nutrition for the epithelial cells, Fibers also promote the development of mucus. The aim of the present study is to evaluate components in the diet that is claimed to be health promoting even though they sometimes can be a hazard to your health. Both fibers and antinutrients can be found in these dietary regimens. The health effects of these products will be studied by analysis of the gut microbiota and the barrier integrity as markers of the health status. Gut microbiota will be analyzed with next generation sequencing and q-PCR (polymerase chain reaction). Diversity and the occurrence of different species will be determined. The barrier integrity will be estimated by analysis of bacterial DNA in blood and presence of live bacteria. The study consists of two different parts: 1a. 60 health volunteers are divided into two groups. One group consumes ordinary dairy based yogurt and the other a yogurt based on vegan products for four weeks to enable a change in the gut microbiota. At start and after four weeks fecal samples and questionnaires about the general health and gastrointestinal symptoms will be retrieved. It should be noted that the compounds offered can be bought in the ordinary shops. 1. b. The same design as above but with IBD patients instead. Their disease activity will be monitored by scoring sheets and regular blood tests as a part of their regular check-up. 2. a. The same design as in 1a but with comparison between a regular meat-based diet and a diet with vegetarian meat substitutes instead. 2b. The same design as I 2a but with IBD patients. Healthy volunteers will be invited wit advertisements. The IBD patients will be recruited at the out-patient clinic at the Dept of Gastroenterology at Skåne university hospital, Sweden. Before inclusion their disease activity will be monitored. The study is a prospective non-randomized intervention study including both men and women. Each individual will serve as their own control. The meals based on meat substitutes will be composed in cooperation with a dietitian. The estimated amount of yogurt is 200-250 gram/day, and the amount of meat is 150-200 gram/day.