One large-scale prospective cohort study conducted in the United States analyzed the health behaviors of approximately 120,000 adults across a thirty-year period. It used this information to understand how lifestyle factors affected lifespan and the risk of death from non-communicable diseases such as heart disease and cancers. They identified five healthy characteristics:
A healthy diet involves eating a variety of foods in the correct proportions and consuming a calorie intake that allows for the maintenance of healthy body weight. Although this varies for everyone, as a general guide, this should include:
- At least five portions of fruit and vegetables per day should account for a third of your daily food intake. Evidence has shown that people who meet this requirement are at a lower risk of developing some cancers and heart disease. One meta-analysis found a dose-response relationship between fruit and vegetable intake and disease, with the risk of death from heart disease dropping by 8% per portion of fruit or vegetables consumed daily, up to ten portions, while cancer risk dropped by 3% per portion.
- Starchy foods, particularly wholegrain varieties which contain more fiber and nutrients than white varieties. Whole grains have been shown to reduce the risk of several cancers, type 2 diabetes and heart disease and promote healthy gut bacteria.
- Lean proteins, especially fish, eggs, and white meat, are essential for cellular repair and provide a range of vitamins and minerals.
- Dairy foods and their alternatives, which are a good source of protein and provide calcium.
- Limited amounts of unsaturated fats.
Physical activity – The World Health Organisation recommends that all adults undertake regular physical activity, including at least thirty minutes of moderate aerobic activity daily, supplemented by at least two weight-bearing activity sessions per week. Being physically fit protects against diseases such as cardiovascular disease, some cancers, diabetes mellitus and osteoporosis and aids in the secondary prevention (i.e., the worsening of symptoms) of such disorders.
Healthy body weight – Maintaining healthy body weight is critical for overall health and protects against numerous diseases. Body mass index (BMI), an estimation of body fat calculated using height and weight, can be a useful indicator of whether body weight is healthy. A normal BMI score ranges between 18.5 and 24.9, a score of 25.0 – 29.9 indicates that an individual is overweight, and a score of 30+ indicates obesity. BMI score is positively correlated with disease risk, with higher scores indicating an increased risk of several diseases, including:
- Type 2 diabetes
- Heart disease
- Liver disease
- Mood disorders
- Reproductive disorders
- Risk of cancers
Being overweight or obese contributes to disease development by altering the hormonal and metabolic profile and placing an increased physical burden on various body sites and organs.