HoldsUp

Daniel Lieberman

Harvard University

Daniel Lieberman is a professor of human evolutionary biology, paleoanthropologist, and author at Harvard. His published research focuses on the biomechanics and energetics of human physical activity, including studies on running kinematics, footwear, and metabolic rates. He also investigates the physiological and metabolic impacts of exercise, such as energy expenditure, myokine secretion, and disease prevention.

67 claims checked on air: 5 context 5 contradicted 7 overstated 41 supported 9 unverified

What they said on air - context

1 citing their own research

0:16:00needs contextmoderateHarvard Professor: “I Tried Every Diet. This Is By Far The W

Consuming extremely high amounts of protein can cause kidney damage.

"eating massive amounts of protein is probably not that harmful, unless you get to ridiculous levels and you can do kidney damage, but you have to really eat a lot of protein for that." (said at 0:16:00)

The speaker's general assertion that high protein intake is not harmful to kidney function in healthy individuals is well-supported by clinical trial evidence. Systematic reviews and meta-analyses of randomized controlled trials demonstrate that high-protein diets (up to and exceeding 2.0 to 3.3 g/kg/day) increase glomerular filtration rate (a normal physiological adaptation known as hyperfiltration) without causing significant changes in serum creatinine or biochemical evidence of renal injury in adults without pre-existing chronic kidney disease. However, there is no established dietary threshold at which protein intake has been proven to cause de novo kidney damage in individuals with normal renal function, though high protein intake can accelerate the progression of renal decline in individuals with pre-existing kidney disease.

1:07:56needs contextmoderateHarvard Professor: “I Tried Every Diet. This Is By Far The W

Hippopotamuses lived in the Thames River region in Southern England approximately 125,000 years ago during the interglacial period.

"125,000 years ago there were hippos frolicking in the Thames when the Neanderthals were hanging out in Southern England." (said at 1:07:56)

The assertion that hippopotamuses inhabited the River Thames region during the Last Interglacial period (the Ipswichian / MIS 5e, approximately 125,000 years ago; dated ~129–116 ka BP) is well supported by British Quaternary mammalian biostratigraphy and fossil deposits (such as the famous fossiliferous Ipswichian deposits in central London/Trafalgar Square and Thames terrace sequences). However, the claim's co-assertion that Neanderthals were present in Southern England alongside them is inaccurate: extensive archaeological research demonstrates a well-known hominin absence/hiatus in Britain during the Last Interglacial (MIS 5e), largely because high sea levels turned Britain into an island before Neanderthals could recolonize it.

1:08:14needs contextlowHarvard Professor: “I Tried Every Diet. This Is By Far The W

The morama bean is the second most consumed food by hunter-gatherers in the Kalahari.

"In addition, for example, hunter-gatherers in the Kalahari, the second most consumed food are a kind of bean; it's called the morama bean. It's their number two food." (said at 1:08:14)

Published ethnobotanical literature confirms that the morama bean (Tylosema esculentum) is a major, highly valued traditional food source for the San and other indigenous populations inhabiting the Kalahari region. However, asserting that it is strictly the "second most consumed food" oversimplifies Kalahari hunter-gatherer diets, as plant reliance varies significantly by geographic sub-region, seasonal availability, and specific indigenous community.

1:09:09needs contextlowHarvard Professor: “I Tried Every Diet. This Is By Far The W

Data from 12 tropical hunter-gatherer populations show high diversity in diet, ranging from nearly all plant food to high animal food intake, rather than a fixed macronutrient ratio.

"There are 12 hunter-gatherer groups for which we have really good data, uh excellent data where people actually measured carefully what they eat, and they're all over the place. Some of them are eating pretty much all plants, almost no no animal food. Some are eating tons of animal food, everything in between." (said at 1:09:09)

Ethnographic and dietary analyses of hunter-gatherer populations show substantial diversity in plant-to-animal food ratios and macronutrient intakes depending on ecoenvironment and geography, rather than a single fixed macronutrient ratio. However, compiled global data indicate that a majority of documented hunter-gatherer societies (73%) derived more than 50% of their energy from animal foods, whereas a minority (14%) derived more than 50% of their energy from gathered plant foods. Thus, while dietary macronutrient ratios vary widely across populations as claimed, animal-dominated diets were substantially more common than plant-dominated diets across documented hunter-gatherer groups.

2:00:58needs contextmoderateHarvard Professor: “I Tried Every Diet. This Is By Far The W

Maltodextrin is a carbohydrate that the human body cannot taste as sugar, functioning as an emulsifier and additive in ultraprocessed foods.

"Things like maltodextrin. If you see maltodextrin in your food, run away. Why? Maltodextrin is a kind of sugar that your body can't actually detect as sugar. It's used as an emulsifier. So, it keeps food from particles from breaking apart. So, foods have a long shelf life. It makes things creamier and smoother, but it wreaks havoc with your metabolism." (said at 2:00:58)

The claim is partially accurate regarding taste perception and food technology, but requires clarification. Maltodextrin is a hydrolyzed starch (glucose polymer) that does not primarily activate the canonical human sweet taste receptor (T1R2+T1R3) like simple sugars (sucrose, glucose, fructose). Psychophysical studies demonstrate that humans can orally detect maltodextrin through an independent complex carbohydrate/starchy taste mechanism rather than as standard sweetness. In food science, maltodextrin is widely used as a bulking agent, carrier, texture modifier, and stabilizer to improve mouthfeel and shelf life, though chemically it is a polysaccharide thickener/stabilizer rather than a classic amphiphilic surfactant emulsifier.

Fact-checked episodes

Publications