The Science behind Nutrition Advice

People often express frustration at nutrition recommendations since they seem to change over the years. Many years ago, butter was “bad”, so everyone switched to margarine. Then with information about trans fats, people thought margarine was bad. Low fat diets were all the rage, then low carb. Why is it so confusing to determine what foods are good for us?

I read an interesting article recently (here) about the problems with trying to do nutrition research. It highlights many aspects. I think the overall reason is that our diets are so complex. The article mentioned historical studies, such as when it was discovered that oranges and lemons (high in vitamin C) prevented scurvy. This study was done on sailors who consumed a very limited diet. We have so many more foods available today, it is hard to isolate the effects of any one single food or food group.

The diversity in our diet is generally a good thing, so we don’t want to take that away. Having a greater variety of fruits, vegetables, grains, and even meats/proteins is excellent, especially across the year.

So can you trust any nutrition research? Yes. How do you know what to believe? Here are my tips:

1) Is it promoting a single food or very narrow food group? Then I would say maybe be skeptical. No one food is going to be a “super food” that will literally change your health. Broad categories such as leafy vegetables, berries, etc, are the types of groups we are looking for.

2) How many studies or people did it look at? A single study is only worth so much. There are “studies” published that combine the results of lots of individual studies. These often show less drastic effects, but are more reliable.

3) Does it make sense? For example, the recent announcement saying a diet high in bacon and red meats increases risk of cancer doesn’t come as a huge shock. We know those are not the best choices to make everyday in our diet. Compare that to a (fictitious) study saying eating half a head of cabbage everyday reduces risk of diabetes by 50%. Why on earth would cabbage (specifically) do that? Who would eat that anyway?

Positive skepticism is the way to approach most scientific research. All of it is testing theories. We just need to sift through to find what makes sense to us.

Happy eating!

Have any nutrition questions? Need help with meal planning or a special dietary need? Send your questions to me at kimberlykmarsh(at)gmail(dot)com, and I will answer them in upcoming posts!