The idea is comparatively recent and certainly is at odds with traditional teaching, which encouraged dietitians and caterers to add cream, butter and other fatty foods to the meals of those diagnosed with malnutrition. But, as Alison is quite clear, it's not at odds with the latest thinking and the newer approach is endorsed by her own membership organisation, the British Dietetic Association (BDA).
And for all the media focus on the problems that obesity brings to the health and welfare of many in our society, malnutrition remains a huge problem affecting the elderly and vulnerable.
Alison says: "When treating malnutrition, one of the things we get taught is that we increase the energy in food, so we add extra calories. But when you look at the evidence base to support his, there isn't one."
The 'gold standard' for dietitians, she points out, is NICE Clinical Guideline 32.
"This says that in treating malnutrition we should look at all the nutrients in diet, which means calories, but also protein, vitamins, fibre and fluid - all the usual things you'd expect. But as dietitians it's only relatively recently we've said 'hang on a minute, isn't that what we're supposed to be doing'."