Humans, perhaps Westerners in particular, tend to share a certain creed that goes something like this: If one is good, two are better.

That’s fine when it comes to dollars in the collection plate or hours spent volunteering, but not so with certain items consumed in the name of health. Think nuts, red wine, dark chocolate, coffee.

Nuts, for instance, once thought to be merely delicious and fattening, are – well, delicious and fattening. They’ve also been shown to be full of all sorts of good things such as omega-3 fatty acids. Thus dietitians recommend an ounce (28 grams) of them (especially walnuts and almonds) several times a week for health benefits.
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Doesn’t it stand to reason that if one ounce is recommended a few times a week, two ounces (56 grams) every day would be better?

In a word, and a very firm one at that: no, says Linda Michalsky, assistant professor of clinical nutrition at the University of Texas Southwestern Medical Centre.