另外我也找到一篇發表在 Nutrition Research 的研究也指出喝全脂牛奶可以降低肥胖的機率,但學者很保守的下了這樣的結論:
In summary, higher total dairy food intake (comprising milk, cheese, and yogurt) was associated with lower prevalences of global and abdominal obesity, and this relationship appears to be driven by whole-fat dairy foods. This study supports the inclusion of recommended intakes of dairy foods, including whole-fat products, as an important part of the diet that could have possible anti-obesity effects.
所以牛奶與減少肥胖風險的關聯,重點可能是整體乳製品的攝取量,但是全脂可以加強這樣的效果!
我在想其中一個原因是全脂的產品比較好喝,所以只要民眾會比較樂意攝取乳製品,而讓整體乳製品攝取量增加,進而降低肥胖的風險。
除此之外,Willett 教授的訪談中其實有提到有些低脂牛奶產品會有添加糖類來取代脂肪的問題:
Also, unfortunately, in many low fat dairy products the fat is replaced by sugar, and these will almost certainly induce more weight gain than the full fat versions.
但是這論點就會被一些書籍或鼓吹喝全脂的人士過度引申,Willett 教授在這邊要說的是泛指很多低脂牛奶產品,可能包含調味乳、低脂優酪乳或低脂乳酸飲品等等,這些都會加入大量的糖類,反而增加熱量的問題,並不是單指低脂牛奶本身!
除此之外,民眾已經了解每天需要喝數份的乳製品,且民眾已被教育脂肪可能帶來的危害,但是卻忽略低脂乳製品(非低脂牛奶)帶來添加糖的風險,因此有些國外報導確實不建議飲用低脂乳製品。
但是我們不應該過度引申這樣的文獻,因為文獻中重視的並不是牛奶是低脂或全脂,而是乳製品中常常會額外添加調味用的糖,尤其在低脂乳製品(低脂乳酸飲料、低脂調味乳等等)!