Eggs for breakfast

Earlier in the week I complained that the Egg Foundation and the Herald were over-interpreting a lab study of mouse brain cells.  The study was a perfectly reasonable, and probably technically difficult, piece of basic biological research.  It’s the sort of research that answers the question “By what mechanisms might different foods affect brain function differently?”.   It doesn’t answer the question “What’s for breakfast?”.

If you wanted to know whether a high-protein breakfast such as eggs really increases alertness there are at least two ways to set up a relevant study.    The first would be an open-label randomized comparison of eggs and something else; the second would be a double-blind study of high-protein and high-carbohydrate versions of the same breakfast.  In both cases, you recruit people and randomly allocate them to higher-protein breakfasts on some days and lower-protein on other days.

In an open-label study you have to be careful to minimise response bias, so you would tell participants, truthfully, that some people think protein for breakfast is better and others think complex carbohydrates are better.  You would have to be careful not to indicate what you believed,  and it would be a good idea to measure some addition information beyond alertness, such as hunger, what people ended up eating for lunch.   There’s always some potential for bias, and one strategy is to ask participants about something that you don’t expect to be affected, like headaches.  This strategy was used in the home heating randomized trial that underlies the government’s ‘warm home’ advertising, which found that asthma was reduced by better heating, but twisted ankles were not.

In a blinded version of the study, you might recruit muesli eaters and, perhaps with the help of a cereal manufacturer, randomize them to higher-protein and lower-protein versions of breakfast.  This would be a bit more expensive, but perfectly feasible.  There would be less risk of reporting bias, since neither the participant nor the people recording the data would know whether the meals were higher or lower in protein on a particular day.  At the end of the study, you unmask the breakfasts and compare alertness.   The main disadvantage of this approach is the same as its main advantage — you learn about higher-protein vs lower-protein muesli, and have to make some assumptions to generalize this to eggs vs cereal or toast.

If it really mattered whether eggs for breakfast increased alertness, these studies would be worth doing.  But the Egg Foundation is unlikely to be interested, since it wouldn’t benefit from knowing the facts.  The mouse brain study is enough of a fig-leaf to let the claim stand up in public, and they don’t want to risk finding out that it doesn’t have any clothes.