And, despite being made with nutrient-heavy yeast, experts say Twiglets do not deliver the same vitamin B12 boost as Marmite. Twiglets contain roughly the same bowel-boosting fibre as a large apple, diet experts sayAre Twiglets healthy? One packet has just 97 calories, half a gram of saturated fat, barely any sugar and a large pinch of salt. 'Compared with many crisps and cheese-based snacks, they are also relatively low in saturated fat, containing just two per cent of the daily 20g saturated fat limit,' she adds. Saturated fat is the type known to increase risk of a build up of 'bad' cholesterol, which can damage arteries and trigger heart attacks and stroke.