Table 2. Phases of the three-step change of diet.

Phase	Aim	Recommendation	Duration
1st phase: Restriction phase with optimization of digestive conditions	Reduction of complaints to the greatest possible extent	Vegetable-based mixed diet with restriction of biogenic amine intake, especially histamine intake. The major dietary measure is the optimization of digestive conditions through: Nutrient optimization, Change of meal composition Principles of an adapted balanced diet (light whole food diet).	10 – 14 days
Phase 2: Test phase	Expansion of food selection taking into account individual influencing factors (stress, menstruation, medication intake, etc.)	Targeted reintroduction of suspected foods while maintaining optimized digestive functions. Soften dietary restrictions. Determination of individual histamine tolerance.	Up to 6 weeks
3rd phase: Permanent nutrition	Permanent, demand-covering nutrient supply with high quality of life	Individual dietary recommendations based on optimized digestive functions, based on the individual’s histamine tolerance taking into account exogenous influencing factors.