Obesity and type 2 diabetes (SACE Stage 2 Nutrition)

What this dot point is asking

You need to explain how overweight and obesity develop, how they link to type 2 diabetes, and which dietary and lifestyle factors are involved in causing and preventing them.

Overweight and obesity

Overweight and obesity mean carrying excess body fat to a level that harms health. The underlying cause is a sustained positive energy balance: energy intake from food and drink exceeds energy used in basal metabolism, activity and digestion, so the surplus is stored as body fat.

Because fat is the most energy-dense nutrient and many processed foods and sugary drinks are high in energy but low in fullness, it is easy to consume more energy than the body needs. Low physical activity reduces energy expenditure and makes a positive balance more likely.

Body mass index (BMI) is one tool used to classify weight relative to height, though it does not measure fat directly and has limits for very muscular people.

Type 2 diabetes

Type 2 diabetes is a condition in which the body cannot control blood glucose properly. Normally the hormone insulin moves glucose from the blood into cells. In type 2 diabetes the cells become resistant to insulin, and over time the pancreas may not produce enough, so blood glucose stays too high.

High blood glucose over years damages blood vessels and nerves, raising the risk of cardiovascular disease, kidney damage, nerve damage and vision problems. Excess body fat, especially around the abdomen, is a major risk factor, which is why obesity and type 2 diabetes are closely linked.

Dietary and lifestyle factors

Energy intake and food choices

Diets high in energy-dense, sugary and fatty foods and drinks promote weight gain and stress blood glucose control.

Sugary drinks and refined carbohydrates

Large amounts of sugar, especially in drinks, add energy with little fullness and raise blood glucose sharply.

Physical activity

Regular activity uses energy, helps maintain a healthy weight and improves the body's sensitivity to insulin.

Prevention and management

A balanced, fibre-rich diet with controlled energy intake, fewer sugary and fatty foods, and regular activity helps prevent and manage both conditions. For type 2 diabetes, steady blood glucose is supported by wholegrains, legumes and vegetables that release glucose more slowly.

Why this matters

Obesity and type 2 diabetes are rising worldwide and are strongly shaped by diet and activity, making them central examples of preventable, diet-related disease. They connect energy balance from Topic 1 with the dietary guidelines and with the social and economic influences on food choice in later topics.

In short, overweight and obesity arise from a long-term positive energy balance and raise the risk of type 2 diabetes through insulin resistance, and balanced eating with regular activity is central to preventing and managing both.