Affordability of different isocaloric healthy diets in Germany—an assessment of food prices for seven distinct food patterns Background: For decades, low-fat diets were recommended as the ideal food pattern to prevent obesity, type 2 diabetes and their long-term complications. Nowadays, several alternatives considering sources and quantity of protein, fat and carbohydrates have arisen and clinical evidence supports all of them for at least some metabolic outcomes. Given this variety in diets and the lack of a single ideal diet, one must evaluate if patients at risk, many of which having a lower income, can actually afford these diets. Aim: We modelled four-week food plans for a typical family of two adults and two school children based on seven different dietary patterns: highly processed standard omnivore diet (HPSD), freshly cooked standard omnivore diet (FCSD), both with German average dietary composition, low-protein vegan diet (VeganD), low-fat vegetarian diet (VegetD), low-fat omnivore diet (LFD), Mediterranean diet (MedD) and high-fat moderate-carb diet (MCD). The isocaloric diets were designed with typical menu variation for all meal times. We then assessed the lowest possible prices for all necessary grocery items in 12 different supermarket chains, avoiding organic foods, special offers, advertised exotic super foods and luxury articles. Prices for dietary patterns were compared in total, stratified by meal time and by food groups. Results: Among all seven dietary patterns, price dispersion by supermarket chains was 12–16%. Lowest average costs were calculated for the VegetD and the FCSD, followed by HPSD, LFD, VeganD, MedD and—on top—MCD. VeganD, MedD and MCD were about 16%, 23% and 67% more expensive compared to the FCSD. Major food groups determining prices for all diets are vegetables, salads and animal-derived products. Calculations for social welfare severely underestimate expenses for any kind of diet. Conclusions: Food prices are a relevant factor for healthy food choices. Food purchasing is financially challenging for persons with very low income in Germany. Fresh-cooked plant-based diets are less pricy than the unhealthy HPSD. Diets with reduced carbohydrate content are considerably more expensive, limiting their use for people with low income. Minimum wage and financial support for long-term unemployed people in Germany are insufficient to assure a healthy lifestyle.