Participants in the 'Organic group' will be assigned an organic diet with very low, or no, content of pesticides. The participants will be instructed to replace at least 50% of their food intake with organic foods.

The participants in the 'Climate friendly and organic diet group' will be assigned a combination of a climate friendly and organic diet generating low emissions of greenhouse gas and having very low levels of pesticides. The target is to reduce the participants' diet-related CO2e to 2.5 kg per person and day. The participants will be instructed to replace at least 50% of their food intake with organic products.

A conventional diet according to the Nordic Nutrition Recommendations (NNR). The participants will get information about the present dietary guidelines and how they can adhere to the guidelines, for example, by implementing the "plate model" for meals and learning about recommended levels of intake of macronutrients, micronutrients, fiber and energy.

The investigators will assess changes in intake of protein in kJ/day, when the participants shifts their diet from conventional food habits to sustainable food habits using a validated food frequency questionnaire called Meal-Q. Questionnaire responses will be converted to daily intake of protein in kJ by linkage to the National Food Composition Table using the NutriCalc program developed by the research group.

The investigators will assess changes in intake of fat in kJ/day, when the participants shifts their diet from conventional food habits to sustainable food habits using a validated food frequency questionnaire called Meal-Q. Questionnaire responses will be converted to daily intake of fat in kJ by linkage to the National Food Composition Table using the NutriCalc program developed by the research group.

The investigators will assess changes in intake of carbohydrates in kJ/day, when the participants shifts their diet from conventional food habits to sustainable food habits using a validated food frequency questionnaire called Meal-Q. Questionnaire responses will be converted to daily intake of macronutrients in kJ by linkage to the National Food Composition Table using the NutriCalc program developed by the research group.

The investigators will assess changes in intake of dietary fiber in kJ/day, when the participants shifts their diet from conventional food habits to sustainable food habits using a validated food frequency questionnaire called Meal-Q. Questionnaire responses will be converted to daily intake of dietary fiber in kJ by linkage to the National Food Composition Table using the NutriCalc program developed by the research group.

The investigators will assess changes in intake of vitamin A, measured in Retinol Equivalents per day (RE/day), when the participants shifts their diet from conventional food habits to sustainable food habits using a validated food frequency questionnaire called Meal-Q. Questionnaire responses will be converted to daily intake of vitamin A in RE by linkage to the National Food Composition Table using the NutriCalc program developed by the research group.

The investigators will assess changes in intake of vitamin D, measured in micrograms per day (μg/day), when the participants shifts their diet from conventional food habits to sustainable food habits using a validated food frequency questionnaire called Meal-Q. Questionnaire responses will be converted to daily intake of vitamin D in μg by linkage to the National Food Composition Table using the NutriCalc program developed by the research group.

The investigators will assess changes in intake of vitamin E, measured in alpha-tocopherol equivalents per day (α-TE/day), when the participants shifts their diet from conventional food habits to sustainable food habits using a validated food frequency questionnaire called Meal-Q. Questionnaire responses will be converted to daily intake of vitamin E in α-TE by linkage to the National Food Composition Table using the NutriCalc program developed by the research group.

The investigators will assess changes in intake of thiamin, measured in milligrams per day (mg/day), when the participants shifts their diet from conventional food habits to sustainable food habits using a validated food frequency questionnaire called Meal-Q. Questionnaire responses will be converted to daily intake of thiamin in mg by linkage to the National Food Composition Table using the NutriCalc program developed by the research group.

The investigators will assess changes in intake of riboflavin, measured in mg/day, when the participants shifts their diet from conventional food habits to sustainable food habits using a validated food frequency questionnaire called Meal-Q. Questionnaire responses will be converted to daily intake of riboflavin in mg by linkage to the National Food Composition Table using the NutriCalc program developed by the research group.

The investigators will assess changes in intake of niacin, measured in Niacin Equivalents per day (NE/day), when the participants shifts their diet from conventional food habits to sustainable food habits using a validated food frequency questionnaire called Meal-Q. Questionnaire responses will be converted to daily intake of niacin in NE by linkage to the National Food Composition Table using the NutriCalc program developed by the research group.

The investigators will assess changes in intake of vitamin B6, measured in mg/day, when the participants shifts their diet from conventional food habits to sustainable food habits using a validated food frequency questionnaire called Meal-Q. Questionnaire responses will be converted to daily intake of vitamin B6 in mg by linkage to the National Food Composition Table using the NutriCalc program developed by the research group.

The investigators will assess changes in intake of folate, measured in μg/day, when the participants shifts their diet from conventional food habits to sustainable food habits using a validated food frequency questionnaire called Meal-Q. Questionnaire responses will be converted to daily intake of folate in μg by linkage to the National Food Composition Table using the NutriCalc program developed by the research group.

The investigators will assess changes in intake of vitamin B12, measured in μg/day, when the participants shifts their diet from conventional food habits to sustainable food habits using a validated food frequency questionnaire called Meal-Q. Questionnaire responses will be converted to daily intake of vitamin B12 in μg by linkage to the National Food Composition Table using the NutriCalc program developed by the research group.

The investigators will assess changes in intake of vitamin C, measured in mg/day, when the participants shifts their diet from conventional food habits to sustainable food habits using a validated food frequency questionnaire called Meal-Q. Questionnaire responses will be converted to daily intake of vitamin C in mg by linkage to the National Food Composition Table using the NutriCalc program developed by the research group.

The investigators will assess changes in intake of calcium, measured in mg/day, when the participants shifts their diet from conventional food habits to sustainable food habits using a validated food frequency questionnaire called Meal-Q. Questionnaire responses will be converted to daily intake of calcium in mg by linkage to the National Food Composition Table using the NutriCalc program developed by the research group.

The investigators will assess changes in intake of phosphorus, measured in mg/day, when the participants shifts their diet from conventional food habits to sustainable food habits using a validated food frequency questionnaire called Meal-Q. Questionnaire responses will be converted to daily intake of phosphorus in mg by linkage to the National Food Composition Table using the NutriCalc program developed by the research group.

The investigators will assess changes in intake of potassium, measured in grams per day (g/day), when the participants shifts their diet from conventional food habits to sustainable food habits using a validated food frequency questionnaire called Meal-Q. Questionnaire responses will be converted to daily intake of potassium in g by linkage to the National Food Composition Table using the NutriCalc program developed by the research group.

The investigators will assess changes in intake of iron, measured in mg/day, when the participants shifts their diet from conventional food habits to sustainable food habits using a validated food frequency questionnaire called Meal-Q. Questionnaire responses will be converted to daily intake of iron in mg by linkage to the National Food Composition Table using the NutriCalc program developed by the research group.

The investigators will assess changes in intake of zinc, measured in mg/day, when the participants shifts their diet from conventional food habits to sustainable food habits using a validated food frequency questionnaire called Meal-Q. Questionnaire responses will be converted to daily intake of zinc in mg by linkage to the National Food Composition Table using the NutriCalc program developed by the research group.

The investigators will assess changes in intake of iodine, measured in μg/day, when the participants shifts their diet from conventional food habits to sustainable food habits using a validated food frequency questionnaire called Meal-Q. Questionnaire responses will be converted to daily intake of iodine in μg by linkage to the National Food Composition Table using the NutriCalc program developed by the research group.

The investigators will assess changes in intake of selenium, measured in μg/day, when the participants shifts their diet from conventional food habits to sustainable food habits using a validated food frequency questionnaire called Meal-Q. Questionnaire responses will be converted to daily intake of selenium in μg by linkage to the National Food Composition Table using the NutriCalc program developed by the research group.

The investigators will assess changes in intake of copper, measured in mg/day, when the participants shifts their diet from conventional food habits to sustainable food habits using a validated food frequency questionnaire called Meal-Q. Questionnaire responses will be converted to daily intake of copper in mg by linkage to the National Food Composition Table using the NutriCalc program developed by the research group.

The investigators will assess the participants "likeability" of the diets by asking how likely they are to continue to adhere to them after the end of the intervention.