Body Mass Index (BMI) is used to assess body weight. It is easy to calculate by dividing weight in kilograms by the square of height in metres. For best health, an adult should have BMI in the range 22-24 kg/m2. Those who have weight above or below that range live shorter lives. An "ideal weight" can be calculated as the weight that would give BMI within that range. Here is a calculator that you can use to work out your BMI and ideal weight.
Many New Zealanders skip breakfast, but that is probably not wise. Starting the working day hungry leads to snacking on high-energy foods during the morning, and probably contributes to an overall increase in energy intake. An "ideal" breakfast is filling but not too high in energy -- for example, a high-fibre cereal.
Most New Zealanders habitually take morning and afternoon tea with a hot or cold drink and biscuits, cake or confectionery. For most, the food taken at this time is quite unnecessary. A simple way to limit daily energy intake is to take a drink only, and decline the biscuits. If soft drinks are taken, the "diet" variety is much to be preferred because most standard soft drinks have a great deal of sugar in them.
Another important component of diet is the amount of dietary fibre. Moderately high fibre content seems to help protect against high cholesterol, against colon cancer and diverticulitis, and against constipation and haemarrhoids (piles). The recommendation is that an adult diet should contain fibre equivalent to five teaspoonsful of bran per day. The form in which it is taken is unimportant -- bran cereal, fruit such as bananas and vegetables such as potatoes are all good sources.
The place of alcohol in diet is controversial. There is evidence that men who drink 1-2 standard drinks per day live longer than those who drink more, but also longer than those who drink less. Women have a lower threshold for alcohol-induced liver disease, and for them the optimum dose seems to be one drink per day. The form in which the alcohol is taken is unimportant -- red wine, white wine, beer and spirits all show similar effect. The mechanism seems to be that alcohol boosts the "good" HDL cholesterol, and protects against arterial disease. The effect is slight, and is not enough to recommend alcohol in the face of religious or moral objection to it, or where there is a history of previous inability to control drinking to moderate levels.