If you've seen my shows and read my books, you may be feeling a bit baffled to find yourself reading an article written by that notorious carnivore Hugh Fearnley-Whittingstall about the joys of eating less meat. I can appreciate that. But I really have been eating a lot less meat lately and I'm feeling almost evangelical about persuading other people to do the same.

Let me be clear: I have not become a vegetarian, nor do I think I ever will. So the dialogue I'm keen to begin with other meat-eaters is not about vegetarianism, it's about vegetables. I would love to persuade you to eat more vegetables. And thereby to eat less meat – and maybe a bit less fish too. Why? To summarise, we need to eat more vegetables and less flesh because vegetables are the foods that do us the most good and our planet the least harm. Do I need to spell out the arguments to support that assertion? Is there anyone who seriously doubts it to be true? Just ask yourself if you, or anyone you know, might be in danger of eating too many vegetables. Or if you think the world might be a better, cleaner, greener place with a few more factory chicken farms or intensive pig units.

We eat too much meat in the west – too much for our own health and far too much for the welfare of the many millions of animals we raise for food. I believe that factory farming is plain wrong – environmentally and ethically. So it saddens me to say that, despite some recent significant gains in the UK on poultry and pork welfare, the problems associated with the industrial production of meat are, globally speaking, as bad as ever.

I still believe in being a selective omnivore, casting a positive vote in favour of ethically produced meat and sustainably caught fish. However, I now understand that in order to eat these foods in good conscience, I have to recognise, control and impose limits on my appetite for them. To that end, over the last 18 months or so, I have undergone a sea change in the way I cook: it began as an exercise, but it became nothing short of a small revolution. It is now the case that most of the meals I eat contain no meat or fish. And I can tell you, with my hand on my heart, that I eat better than ever.

I've often written about the art of making a little meat go a long way, how a few shards of bacon or a sprinkling of chorizo or some scraps of leftover chicken are a perfect way to give a lift to a big salad or add interest and texture to a vegetable soup. So why have I avoided such strategies in my bid to be less carnivorous? Why don't I allow a modest amount of meat into most things? Because it would be a cop-out, that's why! That approach, useful though it is at times, is ultimately the wrong mindset for serious change. It suggests a kind of clinging-on to meat; as if a meal is incomplete without it. That, I think, is the feeling we need to let go of.

We may be increasingly aware of the good reasons to eat less meat, but our cooking culture is still largely based around it. The idea of a fridge entirely free of sausages, bacon, chops or chicken can strike fear into the heart of many a cook. Meat is so familiar, so convenient, the easy route to something we instantly recognise as a "proper meal". But there is absolutely no reason why we can't embrace vegetables in the same way.

As the best vegetarian cooks know, you can produce delicious and balanced flesh-free meals without needing to somehow replace meat. We all require protein in our diets of course (though in fact we don't need a huge amount), but I've little time for veggie sausages and TVP. Instead, I'd rather exploit the vital food value and great culinary potential of pulses, nuts and grains, muddling my chickpeas, kidney beans, walnuts and quinoa with fresh leaves, crunchy roots and sun-ripened fruits: squashes, peppers, courgettes, aubergines and tomatoes, to name but five.

I have to admit that, at first, it was hard to shake off the meat-lover's niggling prejudices. But I can honestly say my anxieties – about cooking without flesh being somehow less satisfying, less flavoursome or less easy – have proved groundless. I have actually found it all rather liberating. I'd go so far as to say that I've embraced a whole new way of eating – one which is more democratic than the traditional meat-and-two-veg model. Without a tyrannical piece of meat dominating the agenda, making everything else feel like a supporting act, I've found a new pleasure in cooking for myself, my family and my friends.

Although there's sometimes a bit of peeling and chopping to be done, there are also a lot of dishes that can be prepared ahead and actually taste the better for it – soups, stews, chillies and dips among them. Veg cooking does not need to be massively time-consuming. There are all sorts of ways to make it fit into a busy life – from cooking soups and sauces in big batches and freezing them, to "cheating" by buying pre-prepared vegetables from the supermarket (it's not my choice to shop like that, but if it gets more of us eating more veg then I'm all for it). In any case, there are plenty of quick and cheery meat-free meals – and they don't all have to be based on pasta (though of course, that's a noble ingredient that can do your veg proud).

But to tell the truth, my tendency now is very much towards meals that give equal weight to several different dishes. Much as I enjoy generous one-pot vegetarian curries, hotpots and lasagnes, I find there's something particularly enticing about a meal made up of several "small" dishes, such as you get with Middle Eastern meze, Spanish tapas, Scandinavian smörgåsbords or Italian antipasti. Vegetable cookery lends itself to such pick-and-mix spreads. It's all so much less predictable and more fun than being a slave to meat.

Civilised, and civilising, this way of eating is all about sharing; about sitting down to a kind of indoor picnic – a range of dishes that are passed around, put down, grazed, picked up and passed around again.

These little dishes often include some kind of hummus or dip: I am inordinately fond of crushed and puréed blends of vegetables, bound and thickened with tahini or smooth peanut butter, laced with spices, herbs, garlic and lemon juice and topped with a trickle of lovely extra-virgin rapeseed or olive oil. My current favourites are a cumin-scented roasted carrot hummus and a fantastic blended beetroot and walnut hummus. Such dips can be whizzed up in minutes, and will sit happily in the fridge for several days, to be dipped into until they're all gone. Alongside, I might serve a tray of garlicky, thyme-infused roasted vegetables, a green salad, some cold frittata or a savoury tart. There might be a bowl of simply cooked and dressed puy lentils or some really good roasted artichoke hearts from a jar.

Contrary to what you might think, a meal based around several dishes needn't require much work. You need only a couple of "prepared" things for a family meal, which you can complement with a simple hunk of good bread and a salad of ripe cherry tomatoes or a pile of scrubbed raw carrots. In any case, in my house, our meze-style dishes tend to be prepared and consumed in a sort of rolling relay from meal to meal. Leftovers from yesterday's supper are often a crucial element of today's lunch. It's a relaxed way of cooking and eating.

Even if I can't tempt you into this way of serving dinner, I hope I can convince you that putting meat and fish to one side, very far from diminishing your diet in any way, can lead you into a vast new area of wonderful, wholesome dishes. Vegetable soups alone offer countless opportunities for experimentation – and if that term "vegetable soup" doesn't inspire you, please think again. I'm not talking about thin, anonymous broths but great, chunky, flavour-packed bowlfuls: soups like the hearty Italian ribollita, full of beans and garlic and olive oil, or the stew-like Chilean porotos granados, packed with pumpkin and sweetcorn and fragrant with oregano, or a refreshing tomato gazpacho – and any number of off-the-cuff, homemade improvisations in between.

There are all manner of "big" dishes you can make without meat that will satisfy your stomach and your tastebuds just as well as a roast dinner or a plate of fish and chips: saucy, sweet and spicy curries and chillies; crisply crusted pies and tarts; hearty, main-meal salads; fabulous lasagnes, soufflés and bakes, such as a gorgeous aubergine parmigiana or a whole, stuffed squash. And I haven't even mentioned bread-based meals yet – homemade vegetable pizzas can be mind-blowing but you don't even have to get out a bag of flour in order to enjoy delicious rarebits and toasties loaded with veg, herbs and cheese.

I am a better cook now than I was a year and a half ago. I feed my family better than I did before. I am far less reliant on that freezer full of meat and fish than I used to be. Our River Cottage cookery school and restaurants serve more, and more exciting, vegetable dishes than we ever have before. I enjoy my cooking, and my eating, more than ever. And that feels wonderful.

Undeniably, we are faced with the very challenging question: how can we eat really well every day without contributing to global warming, the suffering of animals or the pillaging of our precious marine resources? There is one, unequivocal answer: to eat more vegetables. Addressing this issue isn't about giving anything up, it's about filling your boots: embracing a world of fabulous, fresh ingredients and finding some new and irresistible ways to cook and serve them. The crucial thing is the mental shift: after that, I predict you will find it a breeze.

• River Cottage Veg Every Day! is published on 19 September by Bloomsbury at £25. To order a copy for £18 (including free UK mainland p&p), visit the Guardian Bookshop.