"The food we eat and how we produce it determines the health of people and the planet, and we are currently getting this seriously wrong," says Tim Lang, professor of food policy at City, University of London. Lang was part of a recent three-year project, EAT-Lancet, that brought together almost 40 experts from 16 countries with expertise in health, nutrition, environmental sustainability, food systems, economics and political governance.

"We are in a catastrophic situation," Lang says of the project's findings.

When people talk about this topic — if we do at all — the discussion often focuses exclusively on changing the food we choose to eat. And although that's part of the solution, in order to have a sustainable food system, there are actually three things that need to happen, all at the same time.

We need to reduce food waste. We need to improve food production. And we need to change our diets.

And we need to work together — globally — to make those three things a reality.

The stakes couldn't be higher

It's not just our planet that's being harmed by our food choices. Right now, 3 billion people are undernourished, and a billion of those are hungry (malnourished), but many people are actually overnourished.

Two billion people on Earth are eating too much unhealthy food, which is leading to what health researchers have called "epidemic" levels of diabetes and heart disease. According to the Global Burden of Disease report, up to 11 million avoidable, premature deaths can be chalked up to too much of the wrong foods. According to the report, these foods are riskier than "unsafe sex, alcohol, drug, and tobacco use combined."

So while our current global food system is the "single largest emitter of greenhouse gases, the biggest driver of biodiversity loss, and the main cause of deadly algae blooms along coasts and inland waterways," billions of us are also unhealthy. Sounds like a lose-lose situation.

'This goal is within reach'

fruits, vegetables, whole grains A healthy diet includes plenty of fruits, vegetables and whole grains. (Photo: Marilyn Barbone/Shutterstock)

"We need a significant overhaul, changing the global food system on a scale not seen before in ways appropriate to each country's circumstances," Lang says. "While this is unchartered policy territory and these problems are not easily fixed, this goal is within reach and there are opportunities to adapt international, local and business policies."

This is something we can do. Think of it this way: Human beings have adapted what we eat countless times over the course of resettlement, colonization, immigration and migration. In fact, adjusting to new ways of eating is one of the things people are great at. I know my immigrant great-grandparents ate somewhat or even radically different food after they left their home countries of Scotland, Armenia, Wales, Germany and Lebanon.

If our ancestors did it, we can do the same to enable a future that isn't a catastrophe.

baked sweet potatoes, scrambled eggs By topping a baked sweet potato with other healthy foods, you can turn one into a whole meal. (Photo: Amallia Eka/Shutterstock)

Of the three changes needed, one is almost entirely out of the average person's hands: making our food systems more efficient. That's something that specialists and farmers are working on.

Food waste is another big challenge to tackle, and while some of that needs to happen at corporate and government levels, we can definitely all work toward throwing out less at home and work by being more conscious of what we have — and eating it. Keeping a list on the front of the fridge and freezer helps remind me what I already have since it's easy to forget things once they get pushed to the back of the fridge.

Having a "leftover night" where everyone in the family eats leftovers — or does something creative with them — is another tactic. Here are more ideas to cut food waste at home.

The Planetary Health Diet

Lastly, if you are eating meat every day, the time to start cutting back is now. But there's a smart way to do it that won't leave you frustrated. Changing your diet to mimic this one assembled by The Guardian (based on recommendations from the EAT-Lancet study) is possible, though it can seem like a stretch at first glance.

But start with one thing at a time.

The EAT-Lancet recommendations, which the authors call the Planetary Health Diet, start with a vision of where you want to end up: This diet "is symbolically represented by half a plate of fruits, vegetables and nuts. The other half consists of primarily whole grains, plant proteins (beans, lentils, pulses), unsaturated plant oils, modest amounts of meat and dairy, and some added sugars and starchy vegetables," according to the project's site.

buddha bowl By eating a variety of whole, plant-based foods, you'll have your protein needs covered. (Photo: zi3000/Shutterstock)

Notice it's not specific about which vegetables or grains you eat; there's plenty of flexibility for both personal and cultural preferences and what's available locally. When I changed my diet years ago, I focused first on just getting a lot more veggies on my plate. It not only filled me up, but I noticed an immediate positive change in my digestion. Over a couple weeks, I lost a few pounds. Veggies can be eaten raw, cooked, made into soups, mixed into salads or combined with grains. (Think Buddha Bowls — a popular fast-casual restaurant meal choice that usually features a bed of whole grains, a thick middle level of flavorful veggies and a topping of protein like nuts, an egg, spicy tofu and maybe a dressing. You can learn to DIY a Buddha Bowl here.)

Once you've upped your veggies, and found a few that you love — I adore simply baked squash and other root veggies in winter, and greens and tomatoes in the summer — you can start cutting out some meat and subbing in bean dishes.

When should you eat meat? If you continue eating it at all, think about it more like a garnish than the main course. A ham hock, for example, can add flavor to a soup, sauce or grain dish where you want meat flavor but don't really need meat itself.

The EAT-Lancet report suggests, in its specific recommendations: "Aim to consume no more than 98 grams (3.5 ounces) of red meat (pork, beef or lamb), 203 grams (7.1 oz) of poultry and 196 grams (7 oz) of fish per week." This would work out to a healthy serving of chicken and fish once per week, or a regular-small steak every other week.

Having a meat-heavy meal should be reserved for holidays and other special occasions, helping increase appreciation and enjoyment of meat when you do eat it.

A 'lifetime's worth of interesting options'

Who says a sandwich must include meat? Who says a sandwich must include meat? (Photo: JeniFoto/Shutterstock)

Feeling annoyed about the thought of reducing meat? Remember, it's just a habit, like any other. But in this case, it's not just a habit that could be causing health problems for you. We can't afford it on a planet with 10 billion people: "Projections show that a global adoption of a Western diet high in meat intake matched with global population and economic growth will drive significant health burdens and push food systems well beyond environmental limits — multiple studies make the same predictions," the EAT-Lancet study points out.

Reducing sugar can feel similarly difficult, but it's worth remembering that for most of human history, our ancestors lived with very little sugar in their diets. If they could get honey or fruit, that was the extent of the sugar they consumed. I've found my greatest success in cutting sugar by going cold-turkey for four to five days; you'll notice things seem much sweeter if you take a hard break from the sweet stuff.

Changing our diets doesn't have to be about deprivation. If we all think of it more as an exploration, we'll enjoy it more and have more fun figuring out what we like. Keep in mind that, as the report points out: "With more than 30,000 known edible plants, we have a lifetime's worth of interesting options to taste and explore."

Starre Vartan ( @ecochickie ) covers conscious consumption, health and science as she travels the world exploring new cultures and ideas.

How to change your eating habits so your diet isn't 'catastrophic' for the planet
A Lancet study says our eating habits are a "catastrophic situation." We need to reduce food waste, and we need to change our diets. Here's how to get started.