Dieters who snack on nuts, seeds or dried fruit could actually be putting on weight, rather than losing it, say researchers.
The study, carried out by the SupermarketOwnBrandGuide website, has found that nuts and seeds often contain unhealthy amounts of saturated fat and dried fruit is usually high in sugar, reports the Daily Mail.
Just 100g of Brazil nuts contains 16.4g of saturated fat - three quarters of a woman's recommended daily intake, while a handful of dried raisins contains 69g of sugar, more than three-quarters of the recommended amount.
Even pumpkin and sesame seeds contain high levels of saturated fat, it found.
In comparison, 100g of Kit Kat chocolate bar contain 47.8g of sugar.
The research comes as many people begin strict diet regimes as part of New Year resolutions.
"New Year dieters who are tempted to stock up on things like fruit and nuts in order to avoid chocolate could find themselves putting on pounds," website founder Martin Isark said.