It's the fat. Specifically, the shift from saturated to unsaturated fat over the last many decades.
4/ "This suggests that alterations in the intake of saturated relative to unsaturated fat over the past 100 years may have contributed to the decline in BEE reported here, although... further studies in humans are required."
5/ Pretty remarkable finding, from world-class researchers and a world-class database.
6/ There are a few things I disagree with in this paper, but I'll just quote from one of their refs, 36:
“...These studies suggest that the n-6/n-3 ratio per se is an important modulator for white-to-beige thermogenic conversion through oxygenated lipid mediators (oxylipins)..."
7/7. I can live with that. The needle doesn't get moved all the way in one paper. Read the whole thing. (Some nuance omitted here!) Thanks to
2/ "Thirty-seven healthy women were fed two diets. Both diets contained a reduced amount of total and saturated fat. In addition, one diet was low in vegetables and the other was high in vegetables, berries, and fruit. The dietary intake of total fat was...
3/ "...70 g per day at baseline and decreased to 56 g (low-fat, low-vegetable diet) and to 59 g (low-fat, high-vegetable diet). The saturated fat intake decreased from 28 g to 20 g and to 19 g, and the amount of polyunsaturated fat intake increased...
"@eatright and its foundation... received food industry fundings via sponsorships, which are in effect quid pro quos. In a 2015 email, an Academy employee defined a sponsorship as “When a company pays a fee to the Academy/Foundation in return...
2/ "...for Academy/Foundation defined specific rights and benefits.”
"The email reveals the Academy in 2015 was in a sponsorship deal with Abbott and was discussing how the Academy could use its dietitians’ influence in pediatricians’ offices to push Pediasure...
3/ "...one of the pharmaceutical giant’s infant nutritional products. Abbott at the time had in place a two year, $300,000 sponsorship deal.