Tuesday 21 October 2014

trust me, I'm a doctor

Last night I watched episode 2 of Trust Me, I'm A Doctor. Part of the programme was about pasta. It stated or at least implied that pasta is unhealthy, then showed a way of making it healthier. As it says on this page:-

'Although starch is an important part of a healthy diet, it’s easily broken down. As soon as we consume starch the body very quickly starts to digest it, releasing sugars into the blood which in turn causes our bodies to release the hormone insulin. It’s a boom and bust cycle that can take a toll on our health.'

That's very much a generalization. Starch is of two types, amylose and amylopectin. Amylopectin is easily broken down but amylose takes longer. Pasta is already a healthy starch, especially when it is cooked for a shorter time (al dente) and of a type that is thicker. If you want to lower the glycemic index even more you can combine it with protein, or add a mild acid such as lemon juice or vinegar, or add fat or oil. The programme was saying that if you allow cooked pasta to cool then it becomes 'resistant starch'.

So they're saying that pasta is unhealthy, but they have found a way to make it healthy. I'm sure these sorts of statements make the show more sensational, but it gives a distorted picture of what people should be eating. It's a pity because pasta and long-grain rice are the cheapest of foods, cheaper than sugar and processed foods. If you make starch too resistant to digestion then some people suffer bloating. I think it is possible that bad bacteria (and other micro-organisms) will thrive and not beneficial bacteria.

There are types of carbohydrate that are collectively known as FODMAP. This is an acronym used for substances that don't get digested well in the small intestine. They are consumed by bacteria in the large intestine and can cause health problems.

Friday 10 October 2014

new study shows healthy foods more expensive?

There is a study published this week that claims to show that more healthy foods were consistently more expensive than less healthy foods, and have risen more sharply in price over time. There have been a number of studies that claim the same thing and the problem with them is that they have ignored foods such as pasta and rice which are both cheap and healthy.

This new study doesn't do that. It includes a group of foods 'Bread, rice, potatoes, pasta'. The graph below, from the survey, shows that this group is not only the cheapest (in terms of the cost of calories) but hasn't been rising.

So how do they come to the conclusion that healthy foods are more expensive? It all depends where you get the bulk of your calories from. One healthy option is to get most of your calories from pasta, long-grain rice, porridge and other low-GI starchy foods. These are cheap. Pasta and long-grain rice are 40p per kilo form Aldi or Lidl which makes them even cheaper in terms of cost of calories than sugar.

Yellow split peas are the cheapest source of protein. They are also a cheap source of calories. Other pulses are too. People don't need as much protein as they think, and they don't realise that they get a lot of their protein requirements from relatively low-protein sources such as pasta.

Plants such as pulses are always the cheapest source of protein. However, it is good to have some meat, fish and eggs. Also some milk, cheese or other dairy foods. Variety is good because you will be getting more of a range of micronutrients. You don't need much of these though, and if you're poor you can cut down on them.

There's something a bit daft about measuring the cost of high-protein foods in terms of cost of calories, which is what this study does. You don't eat meat, cheese, fish or eggs for the calories. It's even dafter measuring the cost of fruit and vegetables in terms of cost of calories. We should eat very little of things like meat and lots of vegetables.

Vegetables bulk out food, add flavour, and provide micronutrients (vitamins, minerals and things like lutein). The fact that most of them don't come out well in the £s per 1,000 calorie stakes is irrelevant. A 1 kilo bag of mixed frozen vegetables cost about 75p. Poor people can afford them.

I have a problem with their choice of categories. They have five categories of foods. With the 'Bread, rice, pasta, potatoes' category, they're probably averaging prices. Rice and pasta can be incredibly cheap, but there are also expensive brands. Bread, in the form of a sliced loaf, isn't particularly cheap. Flour, however, can be incredibly cheap. Potatoes are cheap if you buy them by the sack from Morrisons but they can be expensive too. So the really cheap calories are even cheaper than what is shown in their graph.

Yellow split peas, other pulses, and animal protein all go into the same category. Yet there is an enormous difference in price, both in terms of cost of calories (which is their criterion) or in terms of cost of protein. There are also big differences between vegetables such as carrots and cabbage, and vegetables such as frozen peas (potatoes although a vegetable are in a different category).

If you eat the average nutritionist's conception of a healthy diet it would include quite a bit of some expensive food items. It doesn't have to though. Vegetarians would argue that meat isn't necessary and vegans would argue that eggs and cheese aren't necessary. So you can eat cheaply and healthily. They've got their facts right but they've interpreted them wrongly.