The data was produced from conducting a feeding trial using male and female 21-day-old piglets as models for humans, comparing high protein (28% dietary protein) and standard protein (18% dietary protein) diets for 4 weeks. The differences in protein intake came from soya, pea, whey and fish proteins. At day 0, faecal microbiota, size, weight, and blood were recorded or taken. At the end of the feeding period (day 52), faeces, urine and colon tissue samples were taken for analysis. Each week the length of the piglets was measured, and every half-week the weight was measured. The data includes microbiota compositions, urinary metabolite concentrations, quantified protein expression of gut barrier function proteins and mucosal immune system associated protein. The code used for the statistical analysis of the data is also included.