Meal patterns, including intermittent fasting - a scoping review for Nordic Nutrition Recommendations 2023.

Introduction: 'Meal patterns' refers to eating frequency, snacking, regularity, and timing. Here also including intermittent fasting. The effect of meal patterns on health is inconsistent and when updating the Nordic Nutrition Recommendations 2023 (NNR2023), summarizing the evidence is important. Aims: To describe the evidence for the role of meal patterns on bodyweight, body composition, and cardiovascular risk factors (i.e. blood pressure and lipid- and glukose metabolism) in healthy people living with normal weight, overweight, or obesity in all age groups. Methods: An initial search in PubMed found 481 reviews, of which 104 were identified based on titles. Of these, 47 were excluded based on title and abstracts. Of the remaining 57 reviews, 16 were included reporting search terms and inclusion/exclusion criteria. In addition, 8 reviews from reference list or known by authors were included. In total, 24 reviews were relevant. Cochrane Library was searched with no results. Results: All reviews were rated low or critically low (AMSTAR 2). No consistent findings on eating frequency and body weight or composition were found in children/adolescents or adults. In snacking, mixed results were found, although among adults, some consistent results showed positive associations between snacking and body weight. In regularity, breakfast skipping showed mixed results in children/adolescents on body weight and composition. Among adults, randomized controlled trials on breakfast skipping showed a minor impact on improved weight loss. In prospective studies on timing, lower energy intake during late afternoon/evening was related to less body weight. Intermittent fasting reduced body weight but was not superior to continuous energy restrictions. Cardiovascular risk factors were assessed in a minority of the reviews, and despite some beneficial effects, the evidence was limited. Conclusion: Given the overall low to critically low quality of the reviews, the evidence is limited and inconclusive. No consistent results providing evidence for setting recommendations for meal patterns were shown. In this regard, meal patterns may vary within the context of an energy balanced and nutritionally adequate diet.