Metabolic fuels diet providing

Besides water, the diet must provide metabolic fuels (mainly carbohydrates and lipids), protein (for growth and turnover of tissue proteins), fiber (for roughage), minerals (elements with specific metabolic functions), and vitamins and essential fatty acids (organic compounds needed in small amounts for essential metabolic and physiologic functions). The polysaccharides, tri-acylglycerols, and proteins that make up the bulk of the diet must be hydrolyzed to their constituent monosaccharides, fatty acids, and amino acids, respectively, before absorption and utilization. Minerals and vitamins must be released from the complex matrix of food before they can be absorbed and utifized. 

In addition to metabolic fuels and protein, the body has a requirement for a variety of mineral salts, in small amounts. Obviously, if a metal or ion has a function in the body, it must be provided by the diet, as the different elements cannot be interconverted. Again, the need is obvious for a growing child as the body grows in size, so the total amounts of minerals in the body will increase. In adults, there is a turnover of minerals in the body, and losses must be replaced from the diet. 

Besides watet, the diet must provide metaboEc fuels (carbohydrate and fat) fot bodily growth and activity protein fot synthesis of tissue proteins fiber for roughage minerals for specific metabolic functions cettain polyunsamtated fatty acids of the n-3 and n-6 famihes fot eicosanoid synthesis and other functions and vitamins, otganic compounds needed in small amounts for many varied essential functions. 

In the following section, we will provide an overview of varions types of dietary components and examples of the pathways involved in ntilizing these components. We will describe the fuels in our diet, the compounds produced by their digestion, and the basic patterns of fuel metabolism in the tissues of our bodies. We will describe how these patterns change when we eat, when we fast for a short time, and when we starve for prolonged periods. Patients with medical problems that involve an inability to deal normally with fuels will be introduced. These patients will appear repeatedly throughout the book and will be joined by other patients as we delve deeper into biochemistry. 

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