Many healthcare practitioners and physicians believe that the only definitive way to identify the foods that are toxic to your body is by using an allergy avoidance diet and keeping a diary of symptoms. (whfoods.org)
The only definitive way to tell — more accurate than time stamps — is to lift up every chicken and feel for yourself. (bonappetit.com)
«The only definitive way of determining psychoactivity is via human experience, which is usually not documented.» (politics.co.uk)