Effects of energy-restricted diets with or without nuts on weight, body composition and glycaemic control in adults: a scoping review

Abstract

Energy-restricted (ER) diets promote weight loss and improve body composition and glycaemic control. Nut consumption also improves these parameters. However, less is known about the combined benefit of these two strategies. This scoping review implemented a systematic search of Medline, Embase and Scopus to identify randomised controlled trials evaluating the effect of ER diets with or without nuts on body mass, body composition and glycaemic control in adults. After reviewing titles and abstracts, 29 full-text articles were screened, resulting in seven studies reported in eight papers that met the inclusion criteria. Energy restriction was achieved by prescribing a set energy target or reducing intake by 1,000-4,200 kJ from daily energy requirements. Interventions ranged from 4-52 weeks in duration and contained 42-84g/day of almonds, peanuts, pistachios or walnuts. While all studies reported that energy restriction resulted in significant weight loss, the addition of nuts to ER diets only demonstrated significantly greater weight loss in approximately half of the included studies (4/7 studies). There was limited evidence to support additional benefits from nuts for body composition measures or glycemic control. Although improvements in weight loss and glycemia were not consistent when nuts were included in ER diets, no study revealed an adverse effect of nut consumption on health outcomes. Future studies could explore the effect of consuming different types and amounts of nuts, combined with various levels of energy restriction on weight, body composition and glycaemic control.