How to turn leftovers into tasty, high-protein meals

In the UK, huge quantities of perfectly good food get thrown in the bin every day. Having some leftover recipes up your sleeve means you can help play your part in addressing this issue. 

How much of the food you buy goes to waste? It might be more than you realise.

According to WRAP, a charity, around a third of the food people purchase in the UK gets thrown away. But most (61%) of what gets wasted is still edible. 

All that food wastage comes at a cost. WRAP estimates that the average four-person British household throws away £1,000 worth of food that could still be eaten every year. Besides the financial impact, food waste that ends up in landfills is also a significant source of climate change-accelerating methane emissions. It’s also just a bit daft to throw so much good stuff away. 

To mark this year’s Zero Waste Week, we’ve put together a list of ideas for recipes using leftovers. 

Read on to learn about:

• The top foods that get wasted in the UK

• General tips for reducing food waste

• A list of high-protein leftover recipes with veg, fruit, and bread

What are the top foods that get wasted in the UK?

According to WRAP’s most recent survey, UK households waste about 6 million tonnes of food per year. Here are the top 10 categories:

1. Fresh vegetables & salads (1.5m tonnes, of which 480k tonnes potatoes)

2. Fresh fruit (960k tonnes, of which 310k tonnes bananas and 110k tonnes apples)

3. Drink (720k tonnes, of which 400k tonnes tea)

4. Meals - home-made and pre-prepared (510k tonnes)

5. Bakery (480k tonnes, of which 350k tonnes bread)

6. Dairy & eggs (460k tonnes, of which 210k tonnes milk)

7. Meat & fish (400k tonnes)

8. Processed veg & salad (170k tonnes)

9. Staple foods (130k tonnes, of which 31k tonnes pasta, 28k tonnes breakfast cereal)

10. Condiments, sauces, herbs & spices (110k tonnes)

How to avoid wasting food

As the numbers above show, most of us are wasting a significant chunk of our food. While the leftover recipes we list below can help, it’s also valuable to know about other strategies for reducing food waste: 

• Meal planning: By creating a weekly meal plan in advance, you’ll only buy the actual ingredients you need. This means fewer comestibles end up as compostables. 

• Create a shopping list: This is a similar idea. Always make a shopping list before heading to the supermarket. When using a list, you’re less likely to make impulse purchases of things you don’t end up eating. 

• Learn how to store food: Fresh foods will last longer when stored correctly. Check online or read the packaging for different kinds of products. If they don’t need to be kept in the fridge, a good rule of thumb is to keep ingredients somewhere cool, dark, and out of the sun.

• Organise your fridge: By keeping your fridge organised, you can see what’s open and make sure nothing goes mouldy at the back. Keep different food types on different shelves, and rotate open packaging to the front.

• Know how long you can keep leftovers in the refrigerator: Most cooked meals can be decanted into a clean container and stored in a fridge at below 5°C for 3-4 days. Reheat meals until piping hot.

• Freeze foods that go off fast: Many foods that go off fast (such as milk, meat, seafood, etc.) can be easily frozen. If you have a bag, box or bottle of ingredients you’re only going to use half of this week, check online for ideas on how to freeze them effectively - including delicate things like herbs.

Delicious, high-protein recipes using leftovers

Whether you have some lettuce wilting at the back of your fridge, a bag of stale bread, last Sunday’s roast potatoes, or some overripe bananas, these leftover recipes can help you turn them into tasty mains, sides, and starters. 

All of these recipes are super versatile. We’ve suggested a primary ingredient (e.g., lettuce), but you can easily substitute it with something similar (e.g., spinach). You will often need some additional store cupboard staples to turn these into proper meals (beans, sauces, pasta, rice, etc.).

Some of these recipes call for pre-cooked ingredients (e.g., leftover roast potatoes), but you can easily replace them with uncooked foods - just boil, steam, or roast as required. Similarly, some of our ideas use raw ingredients (e.g. carrots), but they could easily be replaced with a precooked equivalent from last night’s dinner. 

When deciding which kinds of ingredients to use, we looked at WRAP’s data to choose some of the most commonly wasted food types in the UK. We’ll be focusing on:

• Leftover veg recipes 

• Leftover potatoes recipes

• Leftover bread recipes

• Leftover fruit recipes

To make these meals more substantial and nutritionally complete, we’ve suggested ways to incorporate plant-based protein into these leftover recipes, too. 

Leftover vegetable recipes

Whether you have a bag of sad-looking lettuce approaching its use-by date or some steamed carrot rounds sitting in a plastic container, the following leftover veg recipes show that these ingredients can still shine. 

Stir-fried anything

Practically any cooked or raw veg can be thrown into a wok with some shop-bought noodles or boiled rice to make a quick, healthy meal. Cook your leftover veg with onions, garlic and ginger, throw in some peanuts for protein, and add the noodles/rice. Then, combine with soy sauce, honey, and a squeeze of lime. 

Slightly limp salads—particularly things like lettuce—work surprisingly well in this kind of stir fry. 

Curried anything

Curries are easily some of the best leftover veg recipes. Gently fry onions, garlic, and ginger, stir in a curry powder, your leftover veg, plus some chickpeas for protein. Then, add a tin of tomatoes and leave to simmer. Stir through some dairy or plant-based yoghurt before serving with rice. 

Soups

Soup-based leftover vegetable recipes are an incredibly reliable way of using both raw and cooked veg. Again, start with some gently cooked onion and garlic in oil, add your leftover veg, plus stock and a handful of red split lentils for protein. Once everything’s cooked through, whizz it up with a stick blender. 

Fritters

Almost any vegetable can be turned into fritters. Harder veg (carrots, beetroot, parsnips, squashes) may need to be steamed or boiled first. Others can be cooked from raw. 

Grate or finely chop the veg and mix with sliced onion, herbs, and chickpeas. Make a batter with self-raising flour and eggs, then combine everything in a bowl (if you’re vegan, replace the eggs with water and plant-based milk). 

Warm oil in a large pan, then use two tablespoons to lift the batter into the pan to cook the fritters (they should be about 5cm in diameter and about 1cm thick to ensure even cooking). Once golden-brown on one side, flip and cook through. Serve with yoghurt, dipping sauces, or on their own. 

‘Hey presto’ herb pesto

The classic pesto recipe calls for basil, pine nuts, parmesan, and olive oil. But you can use almost any herb, nut, cheese, and oil mix to slather over pasta, roast potatoes, or even as a sandwich filling. 

Blend any herbs you have (you can also chuck in spinach, lamb’s lettuce, or blanched kale/chard) together with olive or rapeseed oil, practically any kind of nuts (walnuts, almonds, and pistachios are especially good), a garlic clove, a handful of cheese, and perhaps a squeeze of lemon juice. 

Leftover potato recipes

Potatoes are the most wasted kind of vegetable in the UK. This is a terrible shame, since leftover tatties can be turned into all kinds of delicious dishes. 

Bubble and squeak

This one’s a classic. Any kind of cooked potato will do here (boiled, mashed, roasted, baked). Gently fry onion and garlic in a non-stick pan with oil, then add boiled cabbage, brussels sprouts, leeks, or any other veg you have to hand, then stir in the potato (it needs to be roughly mashed first). Press down until a crust forms on the underside, then flip over. 

For protein, serve with poached eggs or baked beans. 

Spanish omelette

This recipe calls for eggs, so it’s not suitable for vegans. 

Liberally cover the bottom of a pan in olive oil, and gently fry sliced onions and potato cubes until soft. You can also experiment by adding any other veg you have in the fridge (peppers, spinach, leeks, peas, etc.). 

Beat six eggs together in a bowl. Pour the onions, potatoes, and oil into the bowl and combine. Return the pan to a low heat, add another tbsp of oil, then pour the egg mixture into the pan. Cook until the underside is golden brown, slide out the pan onto a plate, then flip back onto the pan so the top side is now down, and finish cooking. 

Leftover bread recipes

According to WRAP, Brits throw away seven million slices of bread. Every. Single. Day.

No one likes stale bread, but there’s still an awful lot you can do with a loaf once it’s past its best. 

Make breadcrumbs

Slice up stale bread and leave it to dry out fully (you can also use the oven to do this on a low temperature). Once stale, pop it in your blender and whizz it up into breadcrumbs. These can be stored for months in the freezer. 

Next time you want a crunchy topping for mac ‘n’ cheese, tempura veg, or any kind of breaded meat/fish/veg, you’ll have a key ingredient at hand. 

Bread salads

There are many kinds of salads that use stale bread as a key ingredient, such as Italian panzanella or Cretan Dakos. The bread soaks up the juices from tomatoes, olive oil, vinegar, and fresh herbs, and makes for a brilliant way to use up any stale slices you have. Add cheese or nuts for protein. 

You might like: How to make your diet healthier

Leftover fruit recipes

When life gives you overripe lemons, make lemonade. And the same goes for other fruits too. 

Protein banana pancakes

Mash ripe bananas with eggs, porridge oats, unflavoured protein powder, milk (plant-based or dairy), and baking powder. Fry in oil and serve with more sliced bananas, berries, yoghurt, jams, or maple syrup. 

Any fruit crumble

Apples, pears, berries, and even some exotic fruit can be turned into this classic pudding - and it doesn’t matter if the fruit doesn’t look ‘pretty’. 

Make a crumble mixture using plain flour, oats, butter or dairy-free spread, sugar and flaked almonds (for protein). Toss your fruit with sugar in an oven dish, then sprinkle the crumble mixture on top and bake for 35 mins. 

Sweet stuff: Read our primer on sugar

Leftover recipes: waste not, want not

As these leftover vegetable recipes, leftover bread ideas, and leftover fruit suggestions show, there are endless ways you can reuse the ingredients in the back of your fridge or the bottom of your fruit bowl. 

At Huel, we designed our powders to give you another way to make waste-free breakfasts, lunches, and dinners. Our nutritionally complete powders are long-life (when stored correctly) and allow you to measure out exact portions. That means you won’t generate any extra waste through cooking or food going off. 

Whether you’re making tasty leftover recipes from foods in your fridge or shaking up a delicious Huel meal, why not use this Zero Waste Week to cut back on food waste - and perhaps change your habits for the long term. 

Words by Len Williams