A healthy balanced diet is essential for good health. The key to a healthy and balanced diet is to enjoy a variety of foods in moderation.
Eating no more than needed is important, because over-consumption of anything will unbalance the diet, and in the case of some nutrients - fat and alcohol in particular - could also lead to health problems. As for variety, this will not only make the diet more interesting and enjoyable, but will also help ensure that an individual's requirements for all the micronutrients - vitamins and minerals - are met.
A balanced diet is one that has the correct proportions of each of the energy giving nutrients - fat, protein and carbohydrates (these include starches and sugars).
For health, over around half of our energy intake should come from carbohydrates. The rest of the diet should be made up of protein (around 12-15%) and some fat (less than 30%).
Carbohydrates
Carbohydrates are all the sugars and starches in the diet and they can be divided into three basic groups:
Monosaccharides
These are single molecules of sugar. The monosaccharides are:
Glucose
Fructose
Galactose
Glucose is found free in fruits and as part of the starch molecule in a wide variety of staple foods, such as bread, potatoes, rice, pasta.
Most carbohydrates are eventually digested or converted into glucose by the body for energy (fuel). Fructose is also known as fruit sugar and is found in fruits, vegetables and honey (along with other sugars). It is mostly converted into glucose by the liver. Galactose is part of lactose, the sugar found in milk.
Disaccharides
These are molecules containing two linked monosaccharides They are broken down into the monosaccharides by digestion.
The disaccharides are:
Sucrose which is made up of glucose + fructose
Lactose = glucose + galactose
Maltose = glucose + glucose
Sucrose (table sugar) normally comes from sugar beet and cane, as these are rich plants sources but sucrose can also be found naturally in all fruits and vegetables, and even most herbs and spices. Lactose is found in milk and milk products. Maltose is formed when starch is broken down.
Starches
Starches are simply hundreds of molecules of glucose sugar joined together. When starches are digested, they are first broken down into maltose and then into glucose. So, the only difference between sugars and starch is the size of the molecule. Ultimately, most carbohydrates will end up as glucose to provide that vital fuel to supply the body with energy.
Carbohydrate sources
The bulk of our carbohydrate intake should come from the starchy sources such as bread, rice, potatoes and pasta, and the remainder from more sugary sources such as sugar, fruit and juices. All recent expert committee reviews of the evidence have come to the same conclusion: that sugar has a useful part to play in healthy balanced diet. Furthermore, as most carbohydrate foods, for example pasta or sugars, are eventually broken down into glucose, one type is not appreciably different from another. The key is to enjoy a variety of carbohydrate foods to match individual energy requirements.
Sugar and diet quality
Sugars are often cited as a source of 'empty calories' that displace nutrient-dense foods, resulting in a dilution of diet quality. However, the scientific evidence available to date concludes that sugar can be included as part of a normal, healthy balanced diet and, providing that energy needs are met, it is unlikely to adversely affect the nutrient quality of the diet or the variety of foods consumed. What's more, the body cannot distinguish between added sugars and naturally occurring sugars, such as those in grains, fruit and vegetables, so focusing purely on added sugars rather than the diet as a whole is not particularly useful.
The optimal diet for weight control is a low-fat, high-carbohydrate diet, with the health focus being on limiting dietary fat intakes, especially saturated fat. Research has shown us that dietary fat intakes can be reduced simply by increasing the amount of starchy and sugary carbohydrates in the diet. Sugar also plays a useful role in helping to make a low-fat diet more palatable and therefore easier to stick to.
Carbohydrate's role in appetite
It is also well known that all carbohydrates are satiating, making us feel full, and therefore their consumption helps regulate appetite and food intake.
Sugar and health issues
The expert committees have also noted that the balance of available evidence does not implicate sugar in any of the 'lifestyle diseases' obesity, diabetes, coronary heart disease, or cancer at any site.