There are lots of promises made about diets, many of which fail to eventuate.

But there is one approach to eating that growing evidence suggests could reduce your risk of developing a host of health conditions, from diabetes and heart disease to high cholesterol and dementia.

Eating a plant-based diet — rich in fruits, vegetables, whole grains and legumes — can help slow or prevent various processes of disease that begin long before diagnosis, says dietitian Sue Radd.

"Often we think you either have a disease or you don't. You've either got dementia, or you don't. You've either got high blood pressure, or you don't. You've either got diabetes, or you don't.

"But it's not quite the case. There's a whole pathway from 'not having it' to 'having it'," says Ms Radd.

Diet, she says, is the cornerstone of 'lifestyle' improvement, and eating three times a day gives us great scope to include foods that promote good health.

"Research consistently shows that adopting a natural, minimally-processed, plant-based diet is best because it can simultaneously impact multiple pathways to disease."

Plant-based foods contain a complex mix of useful chemicals and fibre that, when consumed, work in synergy to lower oxidative stress, dampen inflammation, target your microbiome (by feeding the friendly microbes) and lower insulin resistance.

"While individual plant-based foods may contribute certain benefits, the combination of unrefined plant-based foods, consumed regularly, is most powerful."

Ms Radd says it's easy to make meals where vegetables take a starring role ( Supplied: Sue Radd )

Plant power

Adopting a plant-based diet doesn't mean you have to become a vegan or vegetarian, but it does mean consuming a variety of vegetables, legumes, unrefined grains, nuts and seeds, and whole fruits.

Nutrition expert Dr Rosemary Stanton says a diet heavy in plant foods — with or without the addition of animal foods — is the healthiest approach to eating.

"In the past, I think it's fair to say that most nutritional advice centered on nutrients. We were concerned with making sure that everything had enough calcium, iron and enough of this, that and the other," Dr Stanton explains.

"But basically what we need to do is get onto a diet-centred, whole nutrition, food-related pattern of eating.

"We can't dismiss nutrients because obviously they're important. For the general population [though] … if you eat the recommended foods in the Australian Dietary Guidelines from the five food groups, you'll get the nutrients you need. And we've carefully made sure [we] included plant-based options in every food group."

Sue Radd's food rules to live by Enjoy colourful meals based on natural or minimally processed plant-based foods

Enjoy colourful meals based on natural or minimally processed plant-based foods Plan your meals at least one day ahead to help achieve variety

Plan your meals at least one day ahead to help achieve variety Eat three satisfying meals each day at similar times and not too late at night

Eat three satisfying meals each day at similar times and not too late at night Emphasise seasonal produce

Emphasise seasonal produce If you are too busy to cook every night, prepare three recipes in bulk over the weekend and round them off with a fresh salad

If you are too busy to cook every night, prepare three recipes in bulk over the weekend and round them off with a fresh salad Pack lunch and even breakfast for work

Pack lunch and even breakfast for work Sit around the table and enjoy your dinner with someone you love or you can have a good conversation with

Sit around the table and enjoy your dinner with someone you love or you can have a good conversation with Eat slowly and mindfully

Eat slowly and mindfully Don't look for magic bullets. It's the total dietary pattern that matters most.

Food science

Growing evidence suggests plant-based diets may help to better manage or reduce the risk of developing a host of health conditions, including diabetes, heart disease, high cholesterol, obesity and dementia.

For instance, the plant-heavy 'DASH diet' has been found to lower blood pressure and cholesterol, as well as reduce the risk of conditions like heart disease, heart failure, stroke, kidney stones and diabetes.

Then there's the 'portfolio diet', which brings together four key cholesterol-lowering foods: soy protein, nuts and seeds, viscous dietary fibre, and plant sterols.

While each can help lower cholesterol in its own right, their collective effort, according to Ms Radd, is much more powerful.

Research has found the combination of cholesterol-lowering foods in the portfolio diet help to reduce low-density lipoprotein (the 'bad' cholesterol), with the effect being as strong as a starting dose of first-generation statins (cholesterol-lowering drugs).

"These diets are ideal if you wish to avoid or postpone taking life-long medication," says Ms Radd.

The Heart Foundation's chief medical adviser, Professor Garry Jennings, says heart disease develops over decades and prevention measures are much more effective if they start early.

Professor Jennings says statins are generally prescribed to people who have had a heart attack or other vascular disease, or who are at a very high risk.

"The evidence for benefit with statins is so strong that I would consider a healthy diet and statins to be complementary rather than alternatives."

Sicilian orange and fennel salad Ingredients (serves four) 2 very large oranges, peeled with the pith removed

2 very large oranges, peeled with the pith removed 250 g (9 oz) fresh fennel, trimmed of stalks

250 g (9 oz) fresh fennel, trimmed of stalks 2 tablespoons extra virgin olive oil

2 tablespoons extra virgin olive oil flat parsley leaves pulled from stalks, for garnish

Cancer prevention

Cancer prevention is another area in which diet has been found to have a significant impact.

"We used to quote years ago that 30 to 40 per cent of cancers are associated with your diet and lifestyle. A recent meta-analysis has shown it's closer to 60 per cent," Ms Radd explains.

According to Cancer Council Australia, "healthy eating is a first step in reducing your cancer risk".

In its Eat for Health guide, the Cancer Council recommends doubling your serve of vegetables at mealtime, trying a new fruit each week, including vegetables with your lunch, and adding extra vegetables to all recipes.

There are a huge variety of plant-based foods you can incorporate into your diet, but learning how to cook them is essential, says Ms Radd.

Stirring the research pot

Dr Stanton says that in the early years of her career, when she began speaking about cooking as an important part of nutritional education, some of her more senior colleagues snubbed the idea: "What are you doing talking about cooking? We are scientists."

But nutrition and cooking go hand-in-hand, she says, and people need to learn how to cook to better look after their health.

It's an important part of what Dr Stanton terms "food literacy" — being aware of where your food comes from, how it's grown and distributed, and how to prepare it in ways that doesn't ruin its nutritional value.

Becoming familiar with and confident in cooking ingredients you might not have used before is a part of the process, she adds.