- It’s important to define what a healthy diet is
- Making a healthy food choice is not always the easiest task
- All foods can be part of a healthy diet, but, balance between healthy and unhealthy food choices is key
Recently the Rush University Medical Centre reported that high consumption of unhealthy foods frequently found in a “Westernised” diet may lessen the potential benefit of a healthy diet with regards to cognitive decline in an elderly population.
These findings have led to the question of whether unhealthy foods “erase” the positive effect of an otherwise healthy diet.
These findings should, however, be interpreted in context as this is only one study in a specific group of the population and the exact contribution of these unhealthy foods to the overall dietary intake of the population was not quantified.
The findings also only refer to cognitive decline and not to the overall health of the study population. Keeping this in-mind the question “will the pizza of last night undo all of the good achieved by my ‘most-of-the-time’ healthy diet?” warrants further discussion.
A healthy diet
Firstly, a healthy diet should be defined. The World Health Organization defines a healthy diet as a diet that helps to protect against malnutrition (in all its forms) and non-communicable disease (NCDs) such as diabetes, heart disease, stroke and cancer.
The foods included in a healthy diet should, therefore, promote health and prevent disease. Research have indicated that food components such as protein, dietary fibre, essential fatty-acids and micronutrients (vitamins and minerals) promotes our health and provides protection against a number of NCDs.
Vegetables, fruits, legumes (e.g. beans and lentils), nuts, whole grains (oats, wheat and brown rice), fish, lean meats and vegetable oils are good sources of these protective components and are therefore considered to be healthy foods.
These foods are also mainly whole or minimally processed foods. For a diet to be healthy it should contain sufficient amounts of water, macronutrients (carbohydrates, protein and fats) and micronutrients (vitamins and minerals) to meet our requirements.
Unfortunately, no one food contains all of these important food components and therefore a variety of foods should be consumed to guarantee that all of the required food components are received. For that reason, the South African Food Based Dietary Guidelines recommend to “Enjoy a variety of foods”.
To increase the variety of foods in our diet we should eat different foods from various food groups on a daily basis. It is important to keep in mind that this variety of foods should mainly consist of whole or minimally processed foods.
This can be achieved by enjoying mixed meals such as stews with lean meats, fresh vegetables and whole grains, such as whole-grain pasta or brown rice or a lean meat portion with a fresh salad and steamed potato.
Snacking of various fresh vegetables, fruits and nuts during the day also assists in increasing the variety of foods included in our diet.
Unhealthy food choices
Unfortunately, making a healthy food choice is not always the easiest task as we are confronted by many more food options than the whole or minimally processed foods mentioned above.
The majority of these options being mainly highly-processed foods such as pre-packaged sweet and savoury snacks, pre-prepared pie, pasta and pizza dishes, chicken and fish nuggets, sausages, breakfast bars and sugar sweetened beverages.
Food products such as these are also often more affordable and excitingly packaged than the whole- or minimally-processed foods. While these highly-processed foods provide us with great variety and convenience, research have indicated that many of these foods are often energy dense and high in unhealthy fats, free sugars and/or salt.
Frequent consumption of highly-processed foods is associated with an increased intake of total energy (kJ), refined carbohydrates, free sugars, unhealthy fats and salt, and have directly been linked to the development of overweight, obesity and NCDs.
Repeated consumption of these foods is also associated with a decreased intake of dietary fibre, protein and important micro-nutrients such as potassium and calcium, making these highly-processed foods the unhealthy choice.
Therefore, by increasing the food components known to have a negative impact on our health and also by decreasing the intake of protective food components, frequent consumption of highly-processed foods leads to unhealthy dietary patterns that ultimately have a negative impact our health.
When will unhealthy food choices impact the overall healthfulness of one’s diet?
Research has indicated that all foods can be part of a healthy diet, but, balance between healthy and unhealthy food choices is key. Research findings indicate that the quality of our diet increases significantly as the amount of healthier foods regularly consumed increases.
Equally, research has also shown that the quality of our diet significantly decreases the more and frequently we consume unhealthy foods.
Thus, when an unhealthy food is consumed at the expense of a healthy food we often lessen the positive effect that a healthy diet can have on our health.
The current Covid-19 pandemic has once again highlighted why we should prioritise a balanced healthy diet as it plays a key role in maintaining health and supporting our immune systems. A balanced and consistent approach towards our diet is there for great importance.
By balancing the amount of healthy and unhealthy foods we regularly consume we can ensure that we receive the required amount protective food components whilst limiting the amount of fat, free sugars and salt in our diets.
Research has shown that by following the 80/20 approach we can achieve this balance.
This means that we should choose healthy foods at least 80% of the time and allow ourselves to enjoy the less healthy foods 20% of the time. By consistently applying this balanced approach, we will ensure that we receive the required food components to promote health without undoing any good achieved by following a healthy diet.
So will the pizza of last night undo all of the good achieved by a healthy diet? The answer is no, if a healthy diet is consistently followed for 80% of the time and the amount of unhealthy foods are limited to 20% of the time the benefits of regularly consuming healthy foods outweighs the potential negative impact that unhealthy foods may have.
But, we should also remember that a healthy diet consists of more than food choices alone, the quantity of food consumed is also vital.
*Mariaan Wicks is a Senior Lecturer at the Nutrition Department, North-West University, and spokesperson for The Association for Dietetics in South Africa.
