Taking in the science and throwing out the marketing buzzwords, we give you the bottom line on how to really be ‘healthy’ in 2020.

Eating well can be so confusing. There’s no shortage of health advice, but how do you cut through the clutter of mixed messages and dietary dogma? We’ve stripped away the nonsense, found some advisors with proper qualifications and asked them everything you ever wanted to know about healthy eating. This is the guide you need to give yourself the best chance of eating for health.

Dr Emma Beckett is a molecular nutritionist and a lecturer in Food Science and Human Nutrition at the University of Newcastle. She has a PhD in Food Science.

Dr Tim Crowe is a health scientist based in Melbourne and a co-author of Understanding Nutrition, the leading text used in nutrition and dietetics courses in Australia.

Everyone seems to be going vegan. Should I be vegan too?

Dr Tim: Being vegan is definitely on-trend. All the research says plant-based food is consistently linked with good health, so if you are predominantly plant-based you would be doing yourself a world of good. However, people can survive and thrive on a whole range of foods. The evidence doesn’t say that being a vegan is streets ahead of being an omnivore, so long as you are eating a healthy diet to start with. You can be extremely healthy if you choose to include some animal foods in your diet.

Dr Emma: Most people who cut out animal products do it for ethical or environmental reasons, not health reasons. The data doesn’t tend to show that a no-meat diet is better than a moderate or low-meat one. Like all lifestyle regimes, you can do a vegan diet well, or you can do it poorly. If you cut meat but replace it with highly processed plant-based foods, it’s obviously not the same thing as eating a balanced vegan diet. Vegans do need to be careful with nutrients like B12, which aren’t readily available in plant foods: there’s a place for supplements and fortified foods in this case.

Short answer: No, but do eat mostly unprocessed plant food.

FACT: Just 1 per cent of Australians identify as vegans, according to the ABC’s Australia Talks survey conducted last year.

I really let go over the holidays. It’s time to detox, isn’t it?

Dr Emma: When people say “detox”, they usually mean a juice or tea “cleanse”, which restricts or eliminates solid foods. They might be cutting out toxins such as alcohol but what they are really doing is starving themselves. No diets that say they detox are actually doing anything to detoxify. Your liver and kidneys detoxify you: they break down toxins, metabolise them and excrete them in your urine. You don’t need anything dietarily to do that.

Dr Tim: There’s no reason to detox, but where a detox diet can work is to kick off healthy eating habits. That can be a good starting place; you’re not actually detoxifying, but you may be putting less crap into your body.

Short answer: No, just eat more unprocessed plant food.

What about alcohol? Is it bad for me?

Dr Emma: People obsess over carbs, meat or sugar but they happily ignore evidence that alcohol isn’t great for you. The data is mixed: some studies say no level of consumption is safe, others say that no alcohol can be worse than some, but it’s difficult to separate out the confounders there, like wealth. Rich people drink more but they also have better healthcare. From a purely health perspective, you are better off avoiding alcohol.

Dr Tim: Alcohol is not a health food. If you choose to have it as part of your lifestyle, stick within the health guidelines.

Short answer: It’s not great. Don’t drink more than 10 standard drinks a week, zero if you’re pregnant.

I’m worried about my gut bugs – do I have to eat kimchi to help them thrive?

Dr Tim: There is research on the benefits of a healthy gut microbiome, including helping with mood, depression and blood sugar. The best thing you can do is to feed the bacteria you’ve already got. Fibre-rich plant foods such as fruits, vegetables and legumes are like fertiliser for your gut bugs. There’s probably more benefit in eating these prebiotics than dosing up on probiotics such as yoghurt, kimchi and sauerkraut. Kombucha is an on-trend probiotic but there’s no research to say it’s good for you. If you do drink it, it needs to be unpasteurised for there to be any chance of benefit.

Dr Emma: Live cultures in fermented foods can be helpful in ensuring a diversity of gut bacteria. But if you’re not eating fibre, too, you’re just throwing any probiotics down there to die. Good health is also about looking after the good bacteria you’ve got. That’s where fibre comes in – what we call prebiotics. Prebiotics are digested by gut bacteria not by us – they release byproducts like short-chain fatty acids, which may be healthful as they visit other organs.

Short answer: You don’t have to. Fibre is more important than kimchi.

You’re telling me to eat fibre but doesn’t that mean carbohydrates? I’m pretty sure carbs are evil.

Dr Emma: To demonise all carbs is not really great. There are carbohydrates in vegetables, fruits and whole grains and they are perfectly healthy. Reducing carb intake from refined and processed carbs can be a good thing because those foods are a big source of energy and most of us are getting too much of that. What we need is to eat fewer high-carbohydrate foods, such as chips, cakes and lollies, and more foods that are rich in fibre, such as whole grains, fruits and vegetables.

Fibre is actually a carb – it’s really good for you in terms of gut health and controlling weight. When people go low-carb they often go low-fibre or high-fat as a consequence, which can have its own consequences, including missing out on micronutrients such as vitamins and minerals.

Dr Tim: I love carbs. We’ve lived off carbs for thousands of years. The problem is that a lot of the carbs we eat are highly processed white flour and sugar – such as cakes and pastries – without much fibre, vitamins or minerals. That’s our biggest problem, not unrefined powerhouse carbs such as lentils, beans, chickpeas, whole grains and most fruit and veg. That’s where you want your carbohydrates coming from, rather than sugar or doughnuts.

Short answer: The right carbs are healthy, not evil.

But hang on. “Grain-free” gets about 390 million Google results. Are grains bad for me?

Dr Tim: It’s recently popular to hate on grains, but there’s evidence that reveals eating whole grains offers benefits with heart disease, diabetes and weight. For example, some studies show that people who eat diets high in fibre may control their weight better, possibly because those foods increase a sense of fullness. On the other hand, highly refined grains are linked with weight gain, possibly because they don’t make you feel so full.

In a country of abundance, if you are eating fewer grain foods to control your weight that may be a good thing, but don’t throw the baby out with the bathwater. You can have healthy grains that are high in fibre, such as wheat, oats and quinoa, and you can have rubbish grains that are highly processed, such as the flour in cakes. It’s about making a smart choice when you choose grains.

Dr Emma: There are people who say grains are the root of all evil but there are grains and then there are grains. If you’re making a food choice for health – and not every choice is for health, and that’s fine – you want to be looking for a whole grain because they have fibre and micronutrients such as B vitamins, folate, iron, magnesium and selenium. Anything where you can see the chunk of grain is good: it might be brown rice or wholegrain bread. Processed grain foods such as sugary cereal or biscuits are likely to have less of the things that are good for us and more of the things we are trying to reduce. You still need to check the ingredients though – a breakfast cereal may have whole grains and lots of sugar. One good thing doesn’t magically cancel out the bad things.

Processed foods have a place – they are shelf-stable and affordable. It is privileged to say, “Just eat fresh, whole foods.” But the more choices we can make in that direction, the easier it is to have a healthy diet.

Short answer: Whole grains are good.

FACT: Simple carbohydrates – sugars, refined flours – spike blood sugar; complex carbs – fruit, veg, whole grains – contain fibre, which slows sugar absorption.

Still, there are all these glowing people on Instagram eating low-carb keto diets.

Dr Tim: Keto is just another rebadging of a low-carbohydrate diet that has come in and out of fashion over the past 40 years. There’s nothing special about it. You can lose weight on it, but it’s not superior and not many people can stay on a true ketogenic diet long-term because you’re saying goodbye to wonderful foods like bread, pasta and fruit. These diets are incredibly seductive because they are fuelled by anecdotes about people doing really well. As humans, we love stories. We thrive on them. We like them much more than research.

Dr Emma: There are good low-carb diets and bad low-carb diets. The bad ones also restrict fibre. A lot of people who say they’re on a keto diet aren’t on a true keto diet, which can have 90 per cent of the energy coming from fat – it’s very restrictive, difficult and unpleasant. You can lose weight on it, like with any restrictive diet, but weight is just one marker of health. You can be overweight and be nourished and healthy. People may lose weight as a consequence of other health outcomes, some of which will not present themselves until years later. You might be trading being thin right now for being ill in old age.

Short answer: Weight loss is possible on keto but it may not be healthy or sustainable long-term.

FACT: Ketosis is a metabolic process that happens when our body doesn’t have enough carbohydrates to burn for energy, so instead it burns fats.

Fine, I’ll do intermittent fasting then.

Dr Tim: It’s massively on-trend but it’s not a major weight-loss hack. People can lose as much weight on a traditional diet as on fasting. The interest is more in the metabolic benefits that may come from intermittent fasting, such as longevity, but the research is a long way behind supporting those claims. If it works for you then go for it.

I like the way most of the proponents are agnostic about what you should eat. It’s all about the amount of time you don’t eat, or severely restrict your intake – 16 hours, one day, two days out of seven. It doesn’t push diet ideology so it’s really simple so long as you can deal with being hungry.

Dr Emma: There is no evidence that our digestive tract needs a rest, so don’t do it for that reason. But it can be good because it decomplicates things – instead of not eating this or that, it’s about not eating – or eating much less – within certain hours. There are some studies that show good effects for certain people but it’s not magic and it’s not one size fits all. If I don’t eat in the morning, I’ll be hangry all day; eating is important for my mental health, so it’s not a feasible diet for me.

Short answer: Do it if you want but it’s not a magical weight-loss hack.

OK, maybe I’ll just dose up on superfoods. Which ones are best?

Dr Emma: None of them. Superfoods are a marketing construct not science. A superfood is not more nutritious than a non-sexy fruit or vegetable; they just tend to be more hyped and expensive. If you compare acai to apple, it’s not terribly different from a nutritional point of view. They are all good foods but they push the idea that eating healthily is difficult and expensive.

Dr Tim: Superfoods will not die. Every year there are new ones. Most of the superfoods are plant foods and they are good for you but the ones with the most hype tend to be expensive. Anything from the fruit and vegetable section is a superfood – if that’s what you want to call it. Knock yourself out.

Short answer: Meaningless marketing twaddle. Just eat fruit and vegetables.

Which supplements should I spend money on then?

Dr Emma: Only the ones your doctor has told you to take. Most of the time you’re just buying more expensive urine. Vitamins and minerals are essential, but more is not better.

Dr Tim: For the general population, the only one you’d even consider is a general multivitamin. In an ideal world, we would get all the nutrition we need from food, but not many people eat a true healthy diet so a multivitamin is an insurance policy. If you feel your diet is healthy you shouldn’t need it.

Short answer: A healthy diet makes supplements unnecessary. Get your nutrients from fruits, vegetables, legumes and whole grains, and cross pills off your shopping list.

So are you really saying there’s no magic pill?

Dr Emma: Silver bullets and absolutes are a much easier message to sell than telling people to eat in balance and enjoy treats in moderation for the best chance of staying healthy.

Fine, I’ll just go back to eating sugar.

Dr Tim: Absolutely, it’s OK to eat sugar. If you have 80 per cent of your diet right – mostly minimally processed plant foods – adding a bit of sugar to your diet is not going to be an issue, though ideally have less than 25 grams a day.

Dr Emma: You can have some sugar. Sugar that’s bound up in the cells of food (what we call the food matrix) is good. That’s why fruit can have sugar but still be healthy. We want to limit the free sugars: those that have been added to food or released from the original cell structure of the food through juicing or blitzing. When that happens, the way the sugar hits your digestive tract is very different. Many sugar-free recipes use agave syrup or rice malt syrup instead of refined white or brown sugar; they may have slightly more nutrients but they are not really more healthy.

Short answer: Do it, but not too much.

FACT: One cup of fruit juice has the equivalent of about six teaspoons of sugar. A piece of fruit is a better choice as it contains fibre, and has less risk of tooth decay.

What’s the last word on health?

Dr Emma: It’s not one thing that is the dealbreaker. It’s all about balance and moderation. That is a really unsexy message and it’s difficult to sell.

Most of us aren’t eating enough fruit or vegetables and we’re getting too much energy in our diets. Focus on balance, moderation and variety. Don’t get your head turned by so called “easy fixes”. Don’t focus on your weight. Don’t buy into the shame and the bad relationship with food and the wars between all the different tribes about keto or paleo or low-carb.

For me, it’s all about bringing back common sense. Nourish and be kind to your body, and remember that not every food decision is about health. Food is about fun sometimes; I am pro cake. There’s not good food and bad food. It’s the sum of our entire diet that matters, and that’s long-term, not just in one day or week or month.

Dr Tim: If most of the foods you’re eating are plant-based, with lots of fruit, vegetables, legumes and grains, then anything you eat outside of that is really your own taste. If you choose to include some animal foods, that’s perfectly OK, but a well-planned vegan diet can definitely meet your nutritional needs. If you have the core basics right that’s 80 per cent of the battle. Plants for the win.

Short answer: Eat mostly fruit, vegetables, whole grains and legumes. The rest doesn’t matter too much – yes, sometimes you can have your cake and eat it, too.

This story is featured in the healthy issue of Good Food Magazine, available with The Age and The Sydney Morning Herald on Friday, February 7.