Reducing rajas involves avoiding rajasic foods like fried foods, spicy foods, and stimulants such as coffee and alcohol. Don’t over-exercise, don’t over-work, don’t over-consume (that includes material goods as well), and don’t over-think.
Reducing tamas involves avoiding tamasic foods like heavy meats, stale foods, fermented foods, and underripe fruits and vegetables. Don’t over-sleep, don’t over-eat, don’t stay passive or inactive or deliberately avoid taking necessary action.
Increasing sattva, which should always be our focus, involves reducing the rajas and tamas and eating sattvic foods like fresh fruits and vegetables, whole grains and nuts. As a rule, sattvic foods are those that nourish our body and mind and are grown naturally (i.e. organically, without chemicals) and mindfully. They are foods that can be easily digested and provide us with strength and vitality.