The Problem with Low Fat
I have just been reading a review paper published in 2016 regarding micronutrient intake across age groups in the UK (Miller, Spiro and Stanner, 2016).
Working with children and communities, the article makes a point that I have been trying to make for some time: our (excessive?) focus on fat and calories has diverted our attention from the nutritional value of our diets more broadly.
The review references the latest National Diet and Nutrition Survey (Bates et al., 2014) which estimated intake of a selected number of micronutrients for each age group and sex.
Of particular concern is the exceedingly high percentage of teenage girls with intake below the lower reference nutrient intake (LNRI) for a number of micronutrients associated with bone health, mental health, learning and the health of offspring.
For example, a full 46% of girls aged 11-18 are estimated to take in less iron than the LNRI. Iron is an important co-factor in turning the amino acid tryptophan into serotonin, the “calming” hormone. Iron plays a similar role in converting phenylalanine into dopamine. Suboptimal iron levels are also known to effect learning, with overt anaemia leading to fatigue and listlessness.
The authors conclude that micronutrient intakes below the lower reference nutrient intake for selected vitamins and minerals is the result of poor dietary choices. Undoubtedly. But it is also perhaps the result of a focus on low fat eating. Let me explain.
Many of the dietary sources of these essential micronutrients are whole foods. Foods such as meat, full fat dairy, nuts and eggs. While it is true that many of these nutrients are also available in conventionally healthy foods (veg, whole grains), consumers are often only interested in the “headline” story of healthy eating. Unlike me, they have lives outside diet!
The headline has been an unrelenting focus on calories and fat. By eating low fat, one reduces the calories. But low fat often means processed, carbohydrate-based (and cheap?) “food-like substances”, to quote Michael Pollan. Foods that are based on commercial “components”, rather than recognisable ingredients. And foods which have often been processed several times over before reaching our kitchen cupboards, fridges and freezers.
Many of the micronutrients Miller et al. (2016) refer to are heat-sensitive and/or sensitive to processing. I doubt many would consider that a microwave beef lasagna is likely to contain fewer micronutrients than a homemade one. Or even that most people are aware of the degree of processing that goes into the components of that same microwave lasagna.
What is the solution? Quite aside from a desperate need to increase cooking skills, in schools and otherwise, perhaps we should be teaching children again the lists of micronutrients and which foods they can be found in, rather than focussing too much of their attention on traffic lights?