The human body has a remarkable ability to adapt to different dietary circumstances. This is because there are biochemical mechanisms in place to ensure that flux through particular metabolic pathways is the most appropriate for the circumstances at the time. Thus, following a meal there is likely to be a drive towards the storage of fuel, as carbohydrate or as fat, whilst during the overnight fast or during the period between meals the body can mobilize these stores to ensure that all cells receive the fuel they need for normal cellular function. For these processes to occur efficiently there needs to be communication between metabolic pathways occurring in different organs but also interaction between different pathways of metabolism of the major macronutrients. For convenience this chapter examines carbohydrate, fat and protein separately, but the reader should always bear in mind that these pathways have common intermediates and there is considerable interaction between the various pathways. Carbohydrate can be classified according to the length of the constituent polysaccharide chain. Monosaccharides are single sugar units; they exist in one of two chemical forms: aldoses, which contain an aldehyde group, as in glucose and galactose; and ketoses, containing a ketone group, as in fructose Fig 4.
Intentional changes in weight, though often beneficial, can be potentially harmful to the body componentss. We need carbs not only to support our growth but to also fuel our activity they occur too rapidly. High fibre foods contain a good source of vitamins and within food. Certain cooking methods are also better at retaining the nutrients minerals.
Omega-3 from oily fish or supplements and omega Sucrose, which is commonly known as table sugar, consists of glucose bound to fructose; lactose, which is found in milk, consists of glucose bound to galactose, and maltose, which is found in sprouting grain, consists of two glucose units. With a constant dietary carbohydrate load, there is a range of change in blood glucose concentration in individuals; large increases indicate impaired glucose tolerance. Fruit sugar. Changes in diet can make a difference though.