Exposing the health benefits from walnut consumption comes from an appreciation of the walnut as a plant food, with a nutrient content reflecting its own biology. Walnuts have a unique and intriguing nutritional composition. Like all nuts, a large proportion of the walnut is fat, (69%) but 49% is polyunsaturated and 6% is omega 3 in the form of α linolenic acid. The benefits of reducing dietary saturated fat in favour of unsaturated fats have been known for some time and are linked to reductions in risk factors of coronary heart disease, and possibly also type 2 diabetes, by influencing insulin action. Our research has shown that including 30 g/day walnuts in a low fat diet (30% energy from fat) produced favourable shifts in cholesterol levels in people with type 2 diabetes. In a 12-month trial we have also shown a place for walnuts in weight management, with outcomes pending publication. Weight loss and cholesterol change are ‘whole of diet’ effects, but walnuts were shown to substantially influence the dietary fat profile which in turn affects outcomes. Walnuts contain other nutritional attributes in the form of vitamins (walnuts have exceptionally high levels of tocopherol, a form of Vitamin E) and compounds with potent anti-oxidant activity, such as melatonin. The consumption of walnuts has been shown to increase the anti-oxidant capacity of blood which may afford a further protection against disease elements. Describing the benefits of walnut consumption means focusing on the whole food, with all its synergistic attributes, and distilling the effects in the context of a whole diet. From a range of research perspectives, walnuts have proven to be a nutritionally valuable food.