Raw vs. cooked eggs for postexercise muscle protein synthesis Original paper

    In this randomized controlled study, eating cooked eggs after exercise increased amino acid levels more than eating raw eggs, but muscle protein synthesis rates were similar for raw and cooked eggs.

    This Study Summary was published on November 7, 2022.

    Background

    Protein consumption after strength-training exercise stimulates muscle protein synthesis (MPS) and facilitates gains in muscle size and strength. Eggs — a convenient source of high-quality protein and amino acids (AA) — robustly increase postexercise MPS, with maximal MPS observed after taking in 20–40 grams of egg protein.[1]

    Scenes from popular movies depict athletes eating or drinking raw eggs during training, supposedly as a way to enhance this food’s anabolic properties. However, protein digestion from raw eggs is around 40% less than that of cooked eggs.[2] It has yet to be determined whether eating raw eggs or cooked eggs is superior for muscle gain and recovery.

    The study

    In this randomized controlled study, 45 healthy men (average age of 24) performed a single session of resistance training and immediately afterwards ate one of three different breakfasts: 5 raw eggs (30 grams of protein and 23 grams of of fat), 5 cooked (boiled) eggs (30 grams of protein and 23 grams of fat), or a control breakfast consisting of a croissant, butter, and orange juice (5 grams of protein, 20 grams of fat, 47 grams of carbohydrates).

    Blood samples were collected from the participants at baseline (before breakfast) and every 15 minutes after breakfast for 5 hours. A leg muscle biopsy was performed at baseline, 2 hours after breakfast, and 5 hours after breakfast.

    The primary study outcomes were AA concentrations and MPS rate. The secondary outcomes included glucose and insulin levels.

    The results

    Total AA, essential amino acids (EAA), leucine, and branched-chain amino acids (BCAA) were elevated after the consumption of raw and cooked eggs, whereas nonessential amino acids (NEAA) were lowered.

    Eating cooked eggs led to higher levels of total AA, EAA, leucine, BCAA, and NEAA compared to eating raw eggs.

    MPS was increased in all groups but was approximately 20% higher after eating raw and cooked eggs than after the control breakfast — with no differences in MPS between raw and cooked eggs.

    Insulin and glucose levels were increased following the control breakfast but not after consuming raw or cooked eggs.

    Note

    Because this was an acute (short-term) study, we don’t know how the differences in amino acid concentrations between the raw egg and cooked egg group might translate into long-term muscle gains. However, the lack of a difference in the rate of muscle protein synthesis between the raw and cooked egg groups suggests that the benefits persist no matter the preferred method of egg preparation.

    This Study Summary was published on November 7, 2022.

    References

    1. ^van Vliet S, Shy EL, Abou Sawan S, Beals JW, West DW, Skinner SK, Ulanov AV, Li Z, Paluska SA, Parsons CM, Moore DR, Burd NAConsumption of whole eggs promotes greater stimulation of postexercise muscle protein synthesis than consumption of isonitrogenous amounts of egg whites in young menAm J Clin Nutr.(2017 Dec)
    2. ^Evenepoel P, Geypens B, Luypaerts A, Hiele M, Ghoos Y, Rutgeerts PDigestibility of cooked and raw egg protein in humans as assessed by stable isotope techniquesJ Nutr.(1998 Oct)