HoldsUp

Luc van Loon

Luc van Loon is a researcher in the fields of exercise science, sports nutrition, and muscle metabolism. His published research focuses on dietary protein requirements, muscle protein synthesis rates, and the metabolic effects of exercise. He also investigates the impacts of amino acid supplementation and resistance training on muscle mass and recovery across diverse populations, including athletes, older adults, and clinical patients.

55 claims checked on air: 2 context 1 contradicted 4 overstated 41 supported 7 unverified

What they said on air - citing their own research

13 citing their own research

0:01:31supportedhightheir own paperDr. Luc Van Loon: Optimizing Protein Intake & Distribution f

Skeletal muscle protein turns over at a rate of 1% to 2% per day, renewing completely in approximately 50 to 100 days.

"And so for muscle, that happens at a rate of 1 to 2% per day, which means that in, say, 50 to 100 days, you have completely renewed your muscle." (said at 0:01:31)

Human metabolic tracer studies measuring muscle protein synthesis (MPS) and fractional synthetic rate (FSR) consistently show that skeletal muscle protein turns over at approximately 1.0% to 2.0% per day under normal conditions (typically ~1.2% to 1.6%/day in healthy young and older adults). At an average fractional replacement rate of 1% to 2% daily, the theoretical complete turnover of muscle protein occurs across approximately 50 to 100 days, although individual sub-fractions (e.g., mitochondrial, myofibrillar, and sarcoplasmic proteins) turn over at slightly varying rates.

0:34:10supportedmoderatetheir own paperDr. Luc Van Loon: Optimizing Protein Intake & Distribution f

Ingesting 100 grams of protein prolongs digestion and absorption and induces a greater muscle protein synthesis response when measured over 12 to 24 hours compared to smaller doses.

"Now we wanted to do a study to show that if you give 100 grams, which is absolutely not something that I'm suggesting that people should be consuming, that it takes longer to digest everything and that you have a longer stimulation of muscle protein synthesis over a more prolonged period of time. So we also measured not over 6 hours, but over 12 and even 24 hours, and then we see that you get a greater response." (said at 0:34:10)

A randomized trial by Trommelen and colleagues (PMID 38118410) investigated the metabolic fate and muscle protein synthesis response to consuming a 100 g bolus of milk protein versus a 25 g bolus or placebo (0 g) during post-exercise recovery over a 12-hour period using quadruple stable isotope tracers. Ingestion of 100 g of protein resulted in prolonged amino acid digestion and absorption (persisting for over 12 hours) and induced a significantly greater and more sustained postprandial myofibrillar and muscle protein synthesis response compared to the 25 g dose.

0:41:40supportedmoderatetheir own paperDr. Luc Van Loon: Optimizing Protein Intake & Distribution f

A deuterated water study showed no difference in muscle protein synthesis or fat loss between time-restricted eating and non-time-restricted eating.

"we've done a study, a more longer-term study, Imre did that with labeled water, and she did that when um in in Melbourne, where I had a visiting professorship position there, and we didn't see a difference in muscle protein synthesis with the time-restricted eating versus the the non-time-restricted eating... The other thing on on that study was we didn't see differences, or that project I should say, is we didn't see a difference in fat loss." (said at 0:41:40)

The speaker accurately describes a 10-day randomized controlled trial led by Dr. Imre Kouw using deuterated water (D2O) to track muscle protein synthesis (MyoPS) during time-restricted eating (an 8-hour eating window) versus an extended eating control (a 12-hour eating window) in males with overweight or obesity. The study found no statistically significant difference in daily integrated myofibrillar protein synthesis rates (1.28% vs. 1.26% per day) or overall body mass changes between groups.

1:00:40supportedhightheir own paperDr. Luc Van Loon: Optimizing Protein Intake & Distribution f

Boiling or cooking eggs denatures the protein and leads to faster release of amino acids into the circulation compared to consuming raw eggs.

"we did a study to see what the digestion and absorption and muscle protein synthesis is after ingesting raw eggs versus cooked eggs. Now, what is really nice to see, you have exactly the same protein, but cooking actually denatures the protein and results in much more rapid release of these amino acids in the circulation." (said at 1:00:40)

The claim is supported by randomized human trials. Heating (cooking/boiling) denatures egg protein, rendering it significantly more digestible and resulting in a higher, more rapid postprandial increase in circulating amino acids compared to consuming raw eggs. A randomized controlled trial in young men (van Loon group) demonstrated that ingesting 5 boiled eggs led to a 20% higher peak concentration of plasma essential amino acids (EAAs) than ingesting 5 raw eggs (PMID: 36774104). Classical ileal digestibility studies using stable isotopes also showed that cooking egg protein increases true ileal digestibility from ~51% (raw) to ~91% (cooked) (PMID: 9772141). Although the rate of muscle protein synthesis did not differ significantly between raw and boiled egg ingestion in the 2022 trial, the specific statement regarding protein denaturation and the more rapid release of amino acids into the circulation after cooking cooked eggs is accurate.

1:06:20supportedhightheir own paperDr. Luc Van Loon: Optimizing Protein Intake & Distribution f

Most plant-based proteins are deficient in one or more specific essential amino acids, most commonly methionine and lysine.

"and sometimes most of the plant-based proteins are deficient in one or more specific amino acids. That's often methionine and lysine." (said at 1:06:20)

Plant-based proteins typically have lower concentrations of specific essential amino acids compared to animal proteins and human requirement profiles. Legumes are characteristically low in sulfur-containing amino acids (particularly methionine), while cereal grains and other plant sources are commonly limited in lysine. Profiling of various commercially available plant protein isolates demonstrates that methionine and lysine concentrations are consistently lower across most plant sources compared with animal protein isolates and human skeletal muscle protein requirements.

1:06:35supportedhightheir own paperDr. Luc Van Loon: Optimizing Protein Intake & Distribution f

Giving healthy subjects 30 grams of protein extract from pea, gluten, or corn stimulates muscle protein synthesis to a degree not significantly different from dairy protein.

"The last five years, we have been trying the protein extracts from pea and gluten and corn, and actually, if we give in healthy subjects, we give 30 grams, which is quite a lot of protein, we don't see a difference with dairy protein." (said at 1:06:35)

Randomized controlled trials in healthy young adults show that ingestion of 30 grams of plant-derived protein—including corn protein isolate alone or a 30 g blend combining wheat (gluten), corn, and pea protein—stimulates postprandial myofibrillar protein synthesis rates to an extent that does not differ significantly from an equivalent dose (30 g) of high-quality milk/dairy protein.

1:08:47supportedhightheir own paperDr. Luc Van Loon: Optimizing Protein Intake & Distribution f

Corn protein extract has a higher leucine concentration than most animal-derived proteins.

"some, just as corn, is actually higher in leucine than most animal-derived proteins." (said at 1:08:47)

Analytical profiling of protein isolates demonstrates that corn protein has an unusually high leucine concentration (approximately 12% to 13.5% of total amino acid content). This exceeds the leucine content of typical animal-derived proteins, including whole milk (~9.0%), egg (~7.0%), beef/skeletal muscle (~7.6%), casein (~9-10%), and even whey protein isolates (~11-12%).

1:31:58supportedhightheir own paperDr. Luc Van Loon: Optimizing Protein Intake & Distribution f

Prostate cancer patients receiving androgen deprivation therapy who engaged in resistance exercise twice a week increased muscle mass and strength compared to controls who lost muscle mass.

"Now, we thought like, "Hey, how easy is it to increase or prevent the muscle loss?" To some extent, we were modest in this, with only like two resistance exercise sessions a week. We increased muscle mass, we increased strength—control group went down. There was no loss, there was actually an increase in muscle mass, there was an increase in muscle strength." (said at 1:31:58)

The claim accurately reflects the findings of a randomized controlled trial in prostate cancer patients receiving androgen deprivation therapy (ADT). Over a 20-week period of supervised resistance exercise training (performed twice weekly in the study protocol), muscle mass and muscle strength increased in the exercise group, while the usual care control group experienced a decrease in muscle mass and strength.

1:33:28overstatedhightheir own paperDr. Luc Van Loon: Optimizing Protein Intake & Distribution f

The adverse muscular side effects of androgen deprivation therapy (ADT) in prostate cancer patients can be fully overcome with resistance exercise, allowing patients to increase muscle mass and strength.

"The ADT is life-saving, but then all the negative effects of the ADT can be completely, fully overcome with resistance exercise." (said at 1:33:28)

Randomized controlled trials and meta-analyses show that resistance exercise effectively counteracts muscle loss, increases muscle strength, and improves physical function in prostate cancer patients undergoing androgen deprivation therapy (ADT). However, stating that resistance exercise can "completely, fully overcome" "all the negative effects of the ADT" overstates the evidence. While resistance exercise attenuates or prevents the loss of lean mass during ADT, hypertrophic gains are blunted compared to healthy age-matched individuals without testosterone suppression. Furthermore, ADT induces wide-ranging systemic side effects—including bone mineral density loss, metabolic changes, hot flashes, fatigue, and sexual dysfunction—that resistance exercise alone does not completely eliminate.

1:37:11supportedhightheir own paperDr. Luc Van Loon: Optimizing Protein Intake & Distribution f

Cold water immersion immediately following resistance exercise impairs acute muscle protein synthesis and reduces muscle perfusion and amino acid delivery for at least the first six hours compared to thermoneutral recovery.

"And after exercise, we put one leg in cold water and one in thermoneutral water, and we saw that the leg in the cold water did not get the same stimulation of muscle protein synthesis, and basically less of the protein would actually go to the leg—less perfusion, less stimulation of muscle protein synthesis. So at least for the first six hours, it seems evident that acute recovery, in the light of muscle protein synthesis, glycogen restoration, is actually compromised by the lower temperature." (said at 1:37:11)

The speaker accurately describes published randomized within-subject (contralateral limb) experimental studies. In healthy young adults performing resistance exercise followed by single-leg cold water immersion (8°C) versus contralateral thermoneutral water immersion (30°C), postexercise cooling significantly reduced microvascular perfusion (microvascular blood volume), lowered dietary amino acid incorporation into skeletal muscle, and blunted acute (5-hour) myofibrillar protein synthesis rates.

1:42:18supportedmoderatetheir own paperDr. Luc Van Loon: Optimizing Protein Intake & Distribution f

Approximately 5% of the connective protein fraction in skeletal muscle is composed of collagen.

"But if we get a fraction of the muscle is the connective proteins, and of those connective proteins about 5% is collagen." (said at 1:42:18)

Biochemical profiling of skeletal muscle protein subfractions indicates that the isolated muscle connective protein fraction is composed of approximately 4.4 ± 0.9% collagen relative to total protein content (compared to ~1.2% in mixed muscle tissue), with the remainder consisting of intra- and extracellular scaffolding proteins, cell adhesion molecules, and residual myofibrillar proteins.

1:42:32supportedhightheir own paperDr. Luc Van Loon: Optimizing Protein Intake & Distribution f

Ingestion of 20 to 30 grams of collagen protein does not stimulate mixed muscle protein synthesis or intramuscular connective tissue protein synthesis.

"Now, so far, studies have not shown increase in muscle protein synthesis when you ingest collagen... We've done a study to see whether it increases connective protein in muscle; we don't see it, at least not with the 20 grams or the 30-gram amounts." (said at 1:42:32)

Randomized controlled trials utilizing stable isotope tracer methods show that ingesting 20 to 30 grams of collagen protein (or 15 g twice daily) does not stimulate myofibrillar muscle protein synthesis or intramuscular connective tissue protein synthesis above baseline/placebo levels, unlike high-quality complete proteins such as whey.

1:44:40supportedhightheir own paperDr. Luc Van Loon: Optimizing Protein Intake & Distribution f

Connective tissue protein synthesis rates increase in skeletal muscle following physical activity independently of post-exercise protein or collagen intake.

"so in muscle, I think that the availability of the amino acids is not restricting the increase after physical activity, because after physical activity, we see the connective tissue protein synthesis rates go up, but it doesn't seem to be dependent on the amount of protein or collagen that you provide." (said at 1:44:40)

Randomized controlled trials using stable isotope tracers demonstrate that resistance exercise stimulates skeletal muscle connective tissue protein synthesis rates, and that this response is not augmented by post-exercise intake of protein, collagen hydrolysate, or free amino acids compared to placebo.

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