Plain language summary
Globally, around 39% of adults are overweight and 13% obese, and more than one third of American adults are obese. Being overweight or obese is associated with many chronic conditions, such as heart disease, high blood pressure and type 2 diabetes. Weight loss, even at moderate level, can reduce the risk of these obesity-related chronic conditions. Commercial weight-loss diet plans can vary greatly, not only in energy content but also in macronutrient and micronutrient composition. Most plans restrict calories or certain macronutrients, particularly carbohydrate or fat, and in doing so, often overlook micronutrient, i.e. vitamin and mineral, content. Previous studies have shown that many weight-loss plans do not provide adequate amounts of all micronutrients, and in order to reach the reference daily intakes for various vitamins and minerals, dieters would need to increase their calorie intake significantly and often unrealistically. The authors of this paper analysed seven single-day menus of three select commercial diet plans to determine their micronutrient sufficiency. The diet plans included were Eat to Live-Vegan, Aggressive Weight Loss (ETL-VAWL), Fast Metabolism Diet (FMD), and Eat, Drink and Be Healthy (EDH). ETL-VAWL diet provided less than 90% of recommended amounts for B12, B3, D, E, calcium, selenium and zinc. The FMD diet was low in B1, D, E, calcium, magnesium and potassium, while EDH diet didn’t meet the recommended amounts for vitamin D, calcium and potassium. Even after adjusting all the plans to an intake of 2000 kcal/day, several micronutrients were found to remain inadequate (vitamin B12 in ETL-VAWL, calcium in FMD and EDH and vitamin D in all diets). The authors conclude that, in order to reduce the risk of micronutrient deficiencies, more attention needs to be paid to micronutrient rich foods when designing commercial diet plans. Alternatively, these nutrient gaps should be filled in other ways, e.g. using appropriate dietary supplements.