After years of being reviled by nutritionists for being high in fat and calories, nuts became a popular snack during the Atkins/South Beach diet crazes. Although the fat and calorie content of nuts hadn't changed for the better, followers of these diets du jour suddenly felt free to gorge on them because some nuts were discovered to be low in carbohydrates and low on the glycaemic index. However, not all nuts are created equal. They're all relatively high in fat (and there- fore calories), although their fat is the good stuff rather than saturated fat. Nuts with higher percentages of fat - pecans, macadamias and brazils, for instance - go rancid much more quickly than others such as chestnuts and hazelnuts. There's a snob value to nuts: some are considered delicacies while others are more common - compare the peanuts (in foil packets) given to passengers in economy class to the pistachios and cashews (warm and presented in ceramic bowls) served to those in business and first class. It's not that they are more delicious than peanuts but, because they are more expensive due to their relative rarity, they're considered more desirable. If you set out a bowl of mixed nuts, it's almost always the cashews and macadamia nuts that disappear first, leaving the poor, lowly peanuts to languish. Some varieties aren't really nuts, strictly speaking. Although probably only the most rigid botanist would nitpick and point out that you're actually eating legumes or seeds when you say you're eating peanuts or walnuts. Producers of nut snacks don't always make them as healthy as possible. Nuts have plenty of fat and flavour on their own but they're often fried in oil (which adds more calories) or mixed with salt and artificial flavours. If you're trying to be healthy buy unflavoured, dry-roasted nuts.