Last week, I stumbled across a BBC News article entitled How to eat healthily on £1 a day via a story on hacker news. Healthy eating on a budget is something I’m really interested in, but I was horribly disappointed by the article, because i) it didn’t show you how to eat healthily, and ii) it didn’t show you how to eat on £1 per day.

Cheap food is a false economy

Foods the article advocated eating included:

A ham sandwich

Jam

Bacon

Biscuits (!)

Put plainly, these foods are not especially healthy, and some are decidedly unhealthy. (Biscuits, I’m looking at you!)

The diet the article outlines is also woefully deficient in fruits and vegetables. The UK Department of Health and the National Health Service recommend eating 5 portions of fruits and vegetables every day. A portion is defined as 80 grams.

On day 1, the journalist eats 1 apple, 1/4 of a courgette, 1/4 of a red pepper and 50g peas. By my back-of-the-envelope calculations, that’s about 3 portions.

On day 2, he eats 75g mushrooms, a small onion, a banana and “a single leaf” of lettuce with a tomato, for a total of perhaps 4 portions.

On day 5, he eats “four slivers of cucumber”, 50g beans and 25g kale. It’s also possible he eats an apple – the article is unclear. Let’s be generous and assume he does, for a total of 2 portions of fruit and vegetables.

Jam and biscuits are not health foods, and eating a couple of portions of fruit and vegetables a day is not nearly enough. This diet is not healthy. To make matters worse, after consulting a dietitian he concedes he was “well short” on the number of calories he was eating. The diet proposed in the article is a complete failure from a health perspective.

£1 per day means £1 per day

The other big problem with the article, dealt with in some detail here, is that the journalist considers only the fractional cost of foods, regardless of how expensive or perishable the total food is, and indulges in delicacies like African mango. For example, when he uses 2 tablespoons of fresh coriander, he records the cost as 1p (1 pence), even though the bunch of coriander itself cost 50p. Given that fresh coriander only lasts for a few days before wilting, it’s disingenuous to suggest that the first serving costs only 1p, unless he somehow manages to consume another 49 servings of coriander over the next week and accounts for each serving in his budget. (He doesn’t.)

The journalist also takes the absolute cheapest prices he can find from any supermarket. While travel costs are not explicitly included in the budget, it’s unreasonable to assume that someone eating on £1 per day will be able to visit 6 or 7 separate stores just to gather the ingredients for one meal, especially when making these kinds of trips will often require spending money on car travel or public transportation.

What does eating healthily for £1 per day actually look like?

Despite the BBC article being poor in virtually every regard, my curiosity was fired up. Given the constraint of spending only £1 per day, what would the optimally healthy diet look like?

Before I go any further, I want to make clear that I’m not trying to work out how easy or difficult it is for people or families who find themselves in this position — there are clearly a large number of concomitant challenges that I wouldn’t presume to be able to quantify or address.

I’m also making a number of assumptions, some or all of which may not be true for people with a relatively low food budget. My assumptions include:

Access to a fridge and freezer

Access to a well-equipped kitchen with oven, stove-top, pots, pans and other utensils

Time to prepare ingredients and cook

No special dietary needs

Access to a large supermarket

Provision to carry groceries home

When it comes to fractional items, I will assume in the first instance that pricing based on fractional cost is fair so long as the item can be fully consumed before it perishes, and thus the amortized cost of the entire item is included in the budget.

I’ll also assume that most items have to be purchased from one store in order to minimize travel expenses. I’ve decided to use the UK supermarket Asda (a subsidiary of Walmart), partly because their prices seem competitive and partly because they have a comprehensive list of prices online (unlike budget supermarket Lidl or frozen food specialists like Iceland or Farmfoods).

I’m only going to consider regularly priced food products — no special offers or reduced products. I think it makes a great deal of sense to use special offers and reductions when available, but I don’t think it’s fair to consider these resources reliable. If, one day, there’s no food available at a reduced price, you still need to eat.

Aims for the £1-per-day-diet

The UK NHS reports that the average man needs around 2500 calories (kcal) per day and the average woman needs around 2000. My diet will be tailored to provide 2250 kcal per day.

Ideally the diet should satisfy the criteria for a healthy diet disseminated by the UK public health bodies and summarized in the Food Standards Agency Nutrient and Food Based Guidelines for UK Institutions. These include:

5 portions of fruit and/or vegetables per day

At least 18 grams of fiber per day

At least 55 grams of protein per day

Around 50% of food energy from carbohydrate

Around 35% of food energy from fat

Around 15% of food energy from protein

These criteria are not exactly the same as my own for healthy eating, but I think more people will find this investigation useful if I follow government advice rather than relying on my own preferences.

Gathering data

The first step is coming up with a list of candidate foods and working out their true cost. In this context, the most important statistic is the cost per calorie, which for the sake of ease of comparison I have chosen to represent as calories available per £1 of food.

Using data from Asda’s online catalog and the USDA National Nutrient Database for Standard Reference I created a spreadsheet of foods, price per kilogram and calories per £1. This is a naive first-approximation of food cost that doesn’t take into account food spoilage, preparation time or meal planning. Because it would be too laborious to do this for every food Asda sells, foods were selected for inclusion based more or less on my gut feeling about their potential value.

Food Price per kg (£s) Calories per 100g (kcals) Calories per £1 (kcals) Spaghetti (refined flour) 0.38 371 9763 Long Grain Rice (white) 0.40 365 9125 Vegetable oil (rapeseed) 1.00 884 8840 Olive pomace oil 1.50 884 5893 Oats 0.75 372 4960 Brown bread 0.59 229 3881 Peanut butter 1.80 622 3456 Pearl Barley 1.16 352 3034 Yellow split peas (dried) 1.16 341 2940 Olive oil (extra virgin) 3.30 884 2679 Peanuts (salted) 2.40 608 2533 Red kidney beans (dried) 1.56 337 2160 Long Grain Rice (brown) 1.78 370 2079 Dark chocolate (50% cocoa mass) 3.00 515 1717 Spaghetti (wholewheat) 2.00 335 1675 Potatoes 0.47 77 1631 Milk (whole) 0.44 65 1477 Bananas 0.68 89 1309 Houmous (hummus) 3.30 320 970 Onions 0.42 40 957 Carrots 0.46 41 891 Beef liver (fresh) 1.70 135 794 Peas (frozen) 0.99 77 778 Chicken (whole, raw) 2.48 131 528 Red kidney beans (canned) 1.12 58.5 522 Eggs 2.78 143 515 Butternut Squash 1.00 45 450 Apples 1.18 52 441 Green beans (french beans) (frozen) 1.00 39 390 Red cabbage 0.80 31 388 Pork chops (raw) 4.00 155 388 Tomato puree 2.40 92 383 Cottage Cheese 2.17 60 276 Tomatoes (chopped, tinned) 0.78 21 271 Sardines (whole, raw) 3.97 94.8 239 Sardines (in brine) 5.60 133.5 238 Pollock fillets (frozen) 4.00 92 230 Broccoli (frozen) 1.15 26 226 Tuna (flakes in brine) 3.77 71 188 Broccoli (fresh) 2.00 34 170 Courgette (zucchini) 1.62 17 105 Green beans (french beans) (fresh) 4.12 31 75

The most important figure is calories per £1. Because we’re shooting for 2250 calories per day, foods that provide 2250 or more calories per £1 will be our primary sources of food energy. All foods that provide less than 2250 calories per £1 will have to be balanced with foods that provide more.

After creating this table, I created three more columns in my spreadsheet entitled “Weekly amount”, “weekly calories” and “weekly cost”, and added a “totals” row that kept track of the total number of calories per week (out of 15750) and total cost per week (out of £7).

Running the numbers

Fruit and veg

My first goal was fitting in the 5 portions of fruit and vegetables, which I anticipated might be one of the trickier challenges.

Because they’re relatively starchy, bananas are a very cheap source of calories for a fruit — per-calorie, they’re only a little more expensive than milk or potatoes. 1 small banana (80g) is the first daily item in the food budget.

Next, I include one serving (80g) each of carrots and onions because they’re both relatively cheap, can be stored for long periods of time and are very versatile ingredients.

I have a soft spot in my heart for plants in the Brassica genus. In my opinion, they’re some of the healthiest foods around. Optimistically, I add a daily 80g serving of red cabbage.

Lastly, I very much want to include a serving of tinned tomatoes, because they last a really long time, are essential for lots of cooked vegetable dishes and are very healthy. Unfortunately, once opened they’re fairly perishable — the instructions on the label say they should be eaten within 2 days, but at 80g per day a 400g tin would have to last 5 days. For now, I’ll bump the serving size up to 160 grams per day. If this proves too expensive, I’ll have to make adjustments later on.

With the 5 portions of fruit and vegetables covered, here’s what our budget looks like so far.

Food Price per kg (£s) Calories per 100g (kcals) Calories per £1 (kcals) Daily amount (grams) Weekly amount (grams) Weekly Calories (kcals) Weekly Cost (£s) Bananas 0.68 89 1309 80 560 498 0.38 Onions 0.42 40 957 80 560 224 0.23 Carrots 0.46 41 891 80 560 230 0.26 Red cabbage 0.80 31 388 80 560 174 0.45 Tomatoes (chopped, tinned) 0.78 21 271 160 1120 235 0.87

Total: 1361 2.19 Remaining: 14389 4.81

This is pretty sobering; more than a third of our budget has been spent and we have provided less than 10% of the calories we need. On the bright side, the calories from fruit and veg should be far and away the most expensive in our diet.

Fat

There are many promising candidates for cheap carbohydrate-based foods, so next I want to take care of our source of dietary fat.

The cheapest candidate is vegetable oil, which from Asda is made up of 100% rapeseed (canola) oil. However, if at all possible, I’d much prefer to use extra virgin olive oil due to it’s lower omega-6 content and the health-promoting role it appears to play in the Mediterranean diet.

35% of the calories in our diet need to come from fat, so we need around 750 calories worth of fat daily, which is around 85 grams. Let’s assume for the moment that olive oil is the only fat in our diet and add in the full 85 grams per day. That adds 595 grams of olive oil a week to our diet at a cost of £1.96.

Protein

The cheapest food per calorie that’s also a major source of protein is yellow split peas, which provide about 25 grams of protein per 100 grams. (Split peas also have the benefit of being much faster and less laborsome to prepare than other dried pulses.) We need at least 55 grams of protein per day, or a little over 200 grams of split peas. 200 grams is a nice round number, so let’s add that to the daily budget (and assume for now that we get at least 5 grams of protein per day from other food).

That leaves our food budget looking like this:

Food Price per kg (£s) Calories per 100g (kcals) Calories per £1 (kcals) Daily amount (grams) Weekly amount (grams) Weekly Calories (kcals) Weekly Cost (£s) Olive oil (extra virgin) 3.30 884 2679 85 595 5260 1.96 Yellow split peas (dried) 1.16 341 2940 200 1400 4774 1.62 Bananas 0.68 89 1309 80 560 498 0.38 Carrots 0.46 41 891 80 560 230 0.26 Onions 0.42 40 957 80 560 224 0.23 Red cabbage 0.80 31 388 80 560 174 0.45 Tomatoes (chopped, tinned) 0.78 21 271 160 1120 235 0.87 Total: 11395 5.78 Remaining: 4355 1.22

With a little under 4500 calories left, things are now looking more manageable.

Carbohydrate

For breakfast, oats seemed like a no-brainer. Cheap, healthy, and you can store them for a long time. 80 grams a day is one large bowl.

Ideally we’d round things out with a whole-grain carbohydrate, but wholewheat pasta and brown rice are vastly beyond the minuscule budget we have left. Spaghetti is marginally cheaper than rice, but I’ve chosen to go with the latter because it’s so much more versatile. A daily 90g serving of rice neatly plugs the calorie gap and gives us version 0.1 of the £1-per-day budget.

Food Price per kg (£s) Calories per 100g (kcals) Calories per £1 (kcals) Daily amount (grams) Weekly amount (grams) Weekly Calories (kcals) Weekly Cost (£s) Olive oil (extra virgin) 3.30 884 2679 85 595 5260 1.96 Yellow split peas (dried) 1.16 341 2940 200 1400 4774 1.62 Bananas 0.68 89 1309 80 560 498 0.38 Carrots 0.46 41 891 80 560 230 0.26 Onions 0.42 40 957 80 560 224 0.23 Red cabbage 0.80 31 388 80 560 174 0.45 Tomatoes (chopped, tinned) 0.78 21 271 160 1120 235 0.87 Long Grain Rice (white) 0.40 365 9125 90 630 2300 0.25 Oats 0.75 372 4960 80 560 2083 0.42 Total: 15777 6.45 Remaining: -27 0.55

The nutritional breakdown of this diet is fairly positive:

Quantity per day Calories 2254 Carbohydrate 286g Fat 94g Protein 69g Calories from carbohydrate 51% Calories from fat 36% Calories from protein 13% Fiber 68g Sugars 26g Portions of fruit and veg 7 portions Cholesterol 0mg Sodium 78mg

Assessing the diet

Nutrition

The macronutrient ratios are almost exactly in line with our targets — in fact, they are much closer than I was expecting for a first attempt like this. Sugar, sodium and cholesterol are all low, as I would expect in a diet almost entirely lacking in processed food.

Fiber is, if anything, a little high — I’ve talked about the benefits of a high-fiber diet before, but evidence is sparse for additional benefits beyond 25 grams of fiber per day. Our diet provides almost three times that. Such high levels of fiber may cause gastrointestinal discomfort in some people, especially at first. Most of this fiber (50 grams per day) comes from the huge amount of split peas in the diet, and unfortunately, there’s no easy replacement for split peas without sacrificing protein intake. Having said that, we’re currently overshooting our protein goal by 14 grams, so it may be possible to replace some of the split peas with rice or another carbohydrate in order to ease the fiber load.

Under UK guidelines, beans and pulses can count for 1 (but only 1) serving of vegetables per day, meaning the split peas count towards the total. The seven portions breaks down thusly: 1 portion banana, 1 portion carrot, 1 portion onion, 1 portion red cabbage, 1 portion split peas and 2 portions tinned tomatoes.

Practicality and palatability

As might be expected at this early stage, the diet scores low in terms of enjoyment and quality-of-life.

Breakfast seems acceptable to me. Porridge made with water isn’t the most exciting thing in the world, but it’s not terrible. For years I ate it for breakfast every day. There’s also scope for the addition of things like cinnamon at a later stage (the budget intentionally leaves just over 50p a week for these kinds of additions).

Dinner is tougher, but with rice, split-peas, olive oil, tinned tomatoes and onions, there are at least a couple of options: dal with rice, and vegetarian chili. Both options would need spices to be appealing. There is a small amount of space in the budget left for such items — whether or not we’d have to save up to buy them in later weeks depends on how the £1-per-day is available (e.g. weekly or monthly).

Lunch is the real problem with version 0.1. I find it very difficult to think of compelling lunch options with the food available. We may have to resort to eating leftovers from the previous day’s dinner, perhaps with a salad of cabbage, carrot and olive oil on the side. It may also be possible to make split-pea soup, but without any kind of stock I don’t imagine it would be very appetizing.

The only obvious snack food in our diet is the small banana.

Also of concern is the high amount of olive oil, which might be difficult to incorporate into just the evening meal. One option for version 0.2 of the diet would be to make mayonnaise, but that would require both eggs and vinegar.

Fractional items and the food budget

So far, version 0.1 has only considered the fractional cost of foods (although, unlike the BBC article, all the food will be used up).

Running the numbers, the minimum day 1 spend looks like this:

Quantity (grams) Days until next purchase Price (£s) Yellow split peas (dried) 500.00 3 0.58 Bananas 240.00 3 0.16 Tomatoes (chopped, tinned) 400.00 3 0.31 Olive oil (extra virgin) 750.00 9 2.5 Long Grain Rice (white) 1000.00 11 0.4 Red cabbage 1000.00 13 0.8 Oats 1000.00 13 0.75 Carrots 2000.00 25 0.46 Onions 4000.00 50 1.67 Total 7.63

We spend £7.63 on day 1, but most food items will last until the next week, and some longer.

In order to decide how practical it is to spend so much on day 1, we need to decide if our food budget is weekly, bi-weekly or monthly.

Given a weekly food budget (i.e. we get £7 on day 1 and no more money until day 8), we would have to cut some food in the first week. By forgoing onions and red cabbage, we would save enough to buy more split peas, bananas and tomatoes to last out the week. We could then buy onions in week 2.

Given a bi-weekly or monthly budget (i.e. we get £14 or £28 on day 1, but no more money until day 15 or day 29), we can easily afford all the food we need on day 1. In fact, we could buy extra split peas, bananas and tinned tomatoes on day 1 and avoid having to go shopping again until the next week (saving time and reducing transport costs). On a 4-week budget, we could also invest the £2.20 left over on things like spices or condiments.

Buying almost a month’s worth of carrots or almost two months’ worth of onions on day 1 may seem like a big commitment, but stored correctly (carrots in the fridge, onions in a cool, dark place) these foods have very long shelf lives.

Weaknesses of the diet

Aside from the issues of palatability and high fiber that we’ve already covered, there are a few remaining flaws:

We’re abiding by the 5-a-day rule for fruits and vegetables, but we’re obeying the letter of the law rather than the spirit. Eating the same six plant foods for weeks on end will not supply the same variety of phytonutrients as a more varied diet.

As a whole, the diet is very low in omega-3 fatty acids. Oily fish, the richest source of omega-3, is simply beyond our budget. Even tinned sardines or tuna are too expensive to form a regular part of the diet. There are some plant sources of omega-3, but i) we’d likely have to venture beyond Asda and into healthfood stores to find the best candidates, and ii) alpha-linolenic acid, the form of omega-3 found in plants, is poorly converted into longer-chain omega-3 fatty acids the body can actually use .

. Currently, the diet assumes 100% efficiency of preparation, storage and consumption (i.e. no food is wasted at any stage). This is unreasonable, and version 0.2 should include some buffer calories to account for this.

Lessons learned from version 0.1

To me, the biggest lesson is this: avoiding starvation is easy, avoiding malnutrition is hard. As it has been for thousands of years, grains products are the cheapest sources of calories because they’re incredibly thermodynamically efficient. For our £1, we can get over 9000 calories a day from rice, almost 5000 from oats or almost 4000 from bread. We’re in no danger of not having enough to eat. The hard part is finding the right things to eat.

Although I know animal products are expensive, I didn’t fully appreciate the extent; beef liver is far and away the cheapest meat, and it still provides less food energy per £1.00 than a bunch of carrots or bananas. More premium cuts are nowhere near cheap enough for our diet.

Some foods I had always assumed were cheap sources of calories, like canned kidney beans or frozen peas, actually fare quite badly. I find it interesting how my intuition is correct in some areas but way off base in others.

Aims for version 0.2 of the £1-per-day diet

More palatable with firmer meal plans and recipes

Greater variety of foods, particularly fruits and vegetables

Less dietary fiber to ease gastrointestinal distress

Include a calorie “buffer” to leave some room for food wastage

Want to see version 0.2 when it gets posted? Follow via RSS, Twitter or Google+. I’m looking forward to delving back into the spreadsheets to try to make some improvements, and I hope you’ll join me again for the next post.