Objective: Overweight and obesity are serious health issues often caused by a combination of high-energy consumption and limited physical activity. Diets that focus on limiting the energy intake are effective in the short term, but adherence to a diet is difficult and many individuals drop out prematurely. Materials and Methods: The serious game Digest-Inn is designed to increase diet adherence and to stimulate physical activity. The game was evaluated in three studies, assessing playability (in the general population; N = 76), usefulness (in dietetics practice; N = 7), and effectiveness (in reducing weight in overweight individuals; N = 47). Results: In the 3 studies, in total, 108 individuals played the game. The results show that the game supports dietetics practice and increases the effectiveness of the diet as prescribed by a dietitian. Overweight subjects showed an increased diet adherence (from 45% [in nonplayers] to 100% [in players]), increased weight loss (2.2 kg), and their physical activity was 3800 steps per day, during an average study period of 1 month. Conclusion: These results indicate that the game Digest-Inn is valued by dietitians to support the treatment of overweight clients. The game increases the adherence, and the game mechanics may also be of use for other conditions that suffer from low compliance and treatment adherence.
Keywords: Adherence; Diet; Dietitian; Fun; Serious game; Weight loss.