ISSN 1662-4009 (online)

ESPE Yearbook of Paediatric Endocrinology (2021) 18 12.12 | DOI: 10.1530/ey.18.12.12


Pediatr Obes. 2021 Jan;16(1):e12702. doi: 10.1111/ijpo.12702. PMID: 32681547.

In brief: This randomized parallel trial, conducted in the Netherlands, the United Kingdom and Spain, assessed the impact of a high protein/low glycaemic diet vs. medium protein/medium glycaemic diet in reducing insulin resistance in 126 adolescents with overweight/obesity (mean age 13.6±2.2 years). At 2 years, no effect was shown on insulin resistance. The authors concluded that the null findings were due to infeasibility of the diet, insufficient study retention and poor dietary compliance.

Comment: According to a report published in 2019, 45% of adolescent girls and 30% of adolescent boys aged 16–19 years tried to lose weight in the previous year. For both boys and girls, the proportion increased with weight status category. Parallel to the obesity epidemic, the diet industry is growing. Options include: vegetarian, vegan, plant-based flexitarian, keto, intermittent fasting, Atkins, time-restricted eating, Mediterranean diet, blood type, paleo and high protein/low glycaemic diets. The common dominator of all diets is restricting the number of food choices. The key question is: which diet is most likely to produce permanent weight loss?

Even professionals are affected by trends. Therefore, the current study is important in that it aimed to assess the impact of a high protein/low glycaemic diet on insulin resistance. Its strengths lie in the long follow-up of 2 years, and the assessment of compliance to dietary guidance, and assessment of insulin resistance. The 68 participants randomized to high protein diet received a sample menu with a macronutrient composition of 25%/45%/30% energy from protein/carbohydrate/fat, respectively, with overall glycaemic index ≤ 50. The moderate protein group (n=58) received a sample menu with a macronutrient composition of 15%/55%/30% energy from protein/carbohydrate/fat, respectively, and a glycaemic index ≥ 56.

During the 2 years intervention period, 43/68 (63%) of participants in the high protein group dropped out, as did 34/58 (59%) of the moderate protein group. Absolute and relative reported protein intakes (as % of total energy) did not differ from baseline after 1 and 2 years; and no difference in dietary intake was observed between the two groups. Similarly, no difference at any time point was observed between the two groups in insulin resistance, glucose parameters, anthropometry or lifestyles.

High protein diets represent a popular alternative to energy restriction for weight maintenance and weight loss. Data from rodents consistently show that the dietary protein:carbohydrate ratio strongly influences weight gain, probably due to the higher satiating effect of protein. However, food intake in humans is a far more complex. The high drop out rate in both groups here and lack of compliance with diet guidance demonstrates the challenges of conducting long-term studies in adolescents.

Reference: 1. McDow KB, Nguyen DT, Herrick KA, Akinbami LJ. Attempts to lose weight among adolescents aged 16–19 in the United States, 2013–2016. NCHS Data Brief, no 340. Hyattsville, MD: National Center for Health Statistics. 2019.

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