杏吧原创

Read more: Dine in or eat out 鈥� Which is better for you and the planet?

LOW fat, low salt, wholegrain, heart healthy, vegan, organic, free-range, grass-fed, low carb, no added sugar. All these buzzwords, combined with shape-shifting guidelines, befuddling labels and fad diets wrapped up in pseudoscience, can make buying groceries these days fraught. That鈥檚 partly why anything that claims to cut a clear path through the confusion has ready appeal: witness the rise of the 鈥渃lean eating鈥� movement in the past few years. The rigid rules set out by self-appointed blogger gurus have since been shouted down as nonsensical notions of purity rather than coherent nutritional science. But the clean eating evangelists found a following because they promised to simplify, to make decisions about food less overwhelming 鈥� and to provide a world view to match.

I may have avoided the nonsense peddled in the blogosphere, but, like many people, I find the current world of food bewildering at times. My goals are simple enough: I want to come home with the ingredients for tasty meals that will make my family healthier, without spending a fortune. And while I鈥檓 at it, I鈥檇 also like to minimise any harm I might cause to the environment and my fellow humans. That shouldn鈥檛 be so hard, right?

I decided to take a close look at my food choices to see whether I could find a healthier, more sustainable diet. Could I meet both those goals, or would they pull in opposite directions? Equally important for an enthusiastic foodie like me, would I end up with a diet I would actually enjoy eating? And would the whole business be so complicated that only an obsessive would ever bother?

Although it was far more complicated than I hoped to suss the economic impact of my choices on the places that grow food (see 鈥�The quinoa conundrum鈥�), when it came to health and sustainability, what I learned was surprisingly encouraging. 鈥淗ealthy diets frequently have lower environmental impacts,鈥� says of the London School of Hygiene and Tropical Medicine. Better yet, I can get to my goals without having to give up most of the foods I love.

To start, I wanted to figure out how far I could go in minimising my environmental impact. As it happens, , a nutritionist at the University of Aberdeen, UK, has looked at exactly this. She and her colleagues sorted through 82 food groups and crunched the numbers to find .

A sufficiently motivated eater could reduce their greenhouse emissions by a whopping 90 per cent, she found, by sticking to a diet consisting of just seven foods: pasta, peas, fried onions (probably because they have more calories than raw), brassicas (vegetables like cabbages, turnips and broccoli), sesame seeds, dry wholegrain breakfast cereal (which is fortified with lots of nutrients) and confectionery. Sweets don鈥檛 have a huge carbon footprint, so, ironically, in Macdiarmid鈥檚 analysis they are a 鈥済ood鈥� way to get enough calories once you have met your nutrient needs.

As a man who loves his wild mushroom risotto and is not a fan of dental cavities, I am dismayed, to say the least. Macdiarmid is realistic about that. 鈥淪ure, that will have low emissions and meet your dietary requirements, but who鈥檚 ever going to eat it?鈥� she says. Phew. Fortunately, she also found that you don鈥檛 have to go to such extremes to significantly cut carbon emissions.

So I decided to give my current diet a closer look. That means dealing with the elephant in the room: meat. Like most Westerners, I eat more of it than I should, from silky prosciutto to braised lamb shanks to grilled moose steaks (one of the glories of living in Western Canada). The science isn鈥檛 fully settled yet, but diets high in saturated fats 鈥� which are found plentifully in meat and dairy 鈥� have been . Some of the compounds in red meat, and especially in cured meats, such as bacon and ham, also increase the risk of colon cancer. The American Institute for Cancer Research recommends eating , the equivalent of four hamburgers.

Meat鈥檚 environmental cost may be even greater than its health risks. Today, calorie for calorie, beef causes roughly , and requires several times more water. And that鈥檚 only getting worse as the demand for a Western, meat-heavy diet grows throughout the developing world.

鈥淭o feed ourselves more efficiently, meat can be part of the solution鈥�

Faced with that reality, it seems my best choice would be to become vegetarian or vegan. With a little care, such diets can provide all the nutrients you need. This would reduce my environmental footprint, and with none of meat鈥檚 health risks, I could end up healthier too. But not necessarily 鈥� if I were to do what many vegetarians do and switch to a cheese-heavy diet, some studies suggest .

It turns out that vegetarianism may not be the best option. After all, meat is a great protein source and full of iron and vitamin B12 鈥� nutrients that are often in short supply, especially for the world鈥檚 poor. Plus, more than a quarter of Earth鈥檚 surface 鈥� and 鈥� is grazing land, most of it too steep, rocky or arid to grow crops. Grass-fed cattle or sheep are the best way for humans to get calories from this land.

Chickens and pigs can鈥檛 eat grass, but they are still relatively low impact, because they more efficiently convert feed to flesh and produce no methane. They could also live happily on kitchen scraps and other food waste, though in much smaller numbers than with modern, intensive production. In a future where feeding ourselves efficiently is paramount, a little bit of meat and dairy can be an important part of the solution. But 鈥� and it鈥檚 a big but 鈥� we still need to eat far less of it.

Ideally, I would buy only meat raised on 鈥渓eftovers鈥�, but there鈥檚 no straightforward way to do that today for chicken or pork, unless I know the farmer. For beef, I should opt for the pricey grass-fed option, which shouldn鈥檛 break my budget since I鈥檇 only indulge occasionally.

That might have an impact on my carbon budget, though, seeing as these grass-fed animals have a bigger carbon footprint per kilo of meat. This is because they grow more slowly than factory-farmed animals and thus emit more methane. Cutting back dramatically on meat will lessen that impact, says , who heads the at the University of Oxford. But there is no way the world can continue on today鈥檚 meat-heavy path without abandoning notions of animal welfare and opting for factory farming instead. Is this a choice we really want to make?

The takeaway for me is to have more meat-free days, and when I do eat animal products, to cook smaller portions and choose kung-pao chicken or a bit of pork with saut茅ed greens more often than a beef steak or those braised lamb shanks.

I could also make a point of eating more fish, which can provide healthy omega-3 fatty acids as well as protein. In general, this also has a smaller carbon footprint than red meat. The catch is that some species, such as bluefin tuna, orange roughy and Atlantic halibut, are overfished; others, such as farmed shrimp and Atlantic salmon, cause immense damage to nearshore habitats and wild fish. To complicate matters even further, some species such as Pacific salmon are overfished in some places and not others. To make sense of it all, unfortunately there鈥檚 really no choice but to before you buy. For me, that means favouring wild Alaskan salmon and Arctic char farmed in landlocked tanks.

But what of the rest of my dinner plate, the starches and vegetables? Should I be making changes there, too? Unfortunately some of the best foods for my health, such as avocados and tree nuts 鈥� excellent sources of healthy fats 鈥� are among the worst crops environmentally, often grown with irrigation in arid climates. When it comes to growing food, the bottom line is that the environmental impact depends on how and where, which seems worryingly difficult to keep track of. We often think of rice as a water-hungry crop compared with wheat, for example, but in India, most rice is grown with rainwater and most wheat irrigated.

鈥淭he idea that local produce is best is actually a misconception鈥�

So is it fish all over again? Do I have to investigate each item I want to eat? Fortunately, no. 鈥溞影稍�创s will always argue the toss on whether a Brussels sprout is better than an asparagus,鈥� says Macdiarmid. 鈥淏ut how deep do you want to get? My feeling is we have to have some relatively simple messages.鈥� She and the other researchers I spoke to say it boils down to this: eat a wide range of fruits, vegetables, whole grains and legumes. That way I鈥檒l be more likely to cover my nutrient requirements, and I鈥檇 hedge my bets on environmental impact by not eating too much of any one food. So guacamole can stay on the menu, now and then.

Of course, I should be getting all of this stuff as locally as possible, right? I love a stroll around the farmers鈥� market, but the idea that buying local produce is paramount for environmental sustainability is actually a misconception, says Sue Dibb, executive director of , an advocacy group in the UK. Growing tomatoes in UK hothouses of growing them in Spain and shipping them to the UK, for instance. 鈥淚f you care about sustainability, you care how hard it is to produce something, more than where it is produced,鈥� says , a development economist with the International Food Policy Research Institute in Washington DC.

In terms of keeping it local, what that really means is that you can have more of certain foods when they are in season nearby. Out of season, you should cut back on foods that are so perishable that they must be transported by plane, such as the Peruvian asparagus I can buy in the Canadian winter. It鈥檚 not always easy to know which vegetables are flown and which come by road, rail, or ship, but as a general rule, the quicker it will spoil in your fridge, the more likely it is to have arrived by air.

Most of my dinners, to my great enjoyment, also include a glass of wine or beer. There鈥檚 research to suggest that alcoholic drinks, in moderation of course, may have some health benefits. But do I really need it? 鈥淎rguably, these are all unnecessary foods,鈥� says Garnett. She has calculated that alcoholic beverages contribute about 3 per cent of the UK鈥檚 food-related greenhouse gas emissions.

But she and other researchers acknowledge that, like eating meat, alcohol is deeply embedded in culture, and that trampling cultural preferences in the name of saving the planet could be counterproductive. So making the environment more of a priority (see 鈥�The fight for sustainability鈥�) might mean the goal is moderation, rather than abstinence. I鈥檒l raise a glass to that.

So far, this whole process really hasn鈥檛 been that painful. Simply eating more vegetables and having smaller portions of meat and dairy can have a big environmental pay-off. Someone eating a standard, meat-heavy UK diet, for example, would just by consuming fewer animal products and more fruit and vegetables, in keeping with healthy diet recommendations from the World Health Organization. Push just a little harder, and they could achieve a 40 per cent reduction. Macdiarmid, too, found that such simple steps could cut emissions by more than a third.

But the truth is, the two most important steps I could take toward a healthy, sustainable diet require even less drastic measures: eat less and waste less. UN statistics show that the average North American or European has access to , far more than the 2500 that the UK鈥檚 National Health Service recommends for the average man. (For women, the recommendation is roughly 2000 calories per day.) That鈥檚 why my waist 鈥� like that of most people in wealthy countries 鈥� has thickened a bit over the years.

鈥淭he surprising truth is, it鈥檚 easy to make a difference 鈥� without becoming a fanatic鈥�

And a quarter of all the food purchased in the UK , according to the Waste and Resources Action Programme (see pie chart). In the US, it鈥檚 one-fifth. About two-thirds of that waste is avoidable, thrown out mostly because it has spoiled (like the leftover rice and half-loaf of mouldy bread I just binned), or because people have cooked or served too much. So if I want to trim my own food waste, I merely need to pay closer attention to how much I buy and how much I cook at each meal.

If I鈥檓 honest, I began this project braced for disappointment. Diving into the morass of messages about food, sustainability and health, I worried I would come away more confused than I started, or faced with a diet I just wouldn鈥檛 want to eat. But the surprising 鈥� and reassuring 鈥� truth is that it鈥檚 easy to make a difference, even without becoming a fanatic about it. I don鈥檛 have to turn vegetarian or vegan, because I can reduce my environmental footprint almost as much just by cutting back on meat and other animal products. And I can bring a little more awareness to where my food comes from and how it got to my plate. That鈥檚 a pretty good recipe for a healthier planet 鈥� and a healthier me.

This article appeared in print under the headline 鈥淔ood for thought鈥�