A study from the prestigious peer-reviewed journal The Lancet, stating that low-carb dieting may cut your life short by four years, has made headlines in major popular newspapers and news channels ranging from BBC to Reader’s Digest to USA Today. Public health authorities are quoted saying that low-carb diets could be incredibly damaging to your long-term health.
This is MISLEADING, because it skates over two big questions: First, what kind of carbs are you avoiding – processed or unprocessed? Second, are you replacing carbs with plant-based or animal-based proteins and fats? Let me expand on this a little.
First of all, you know that any lifestyle based on “diets” and “dieting” is bad for your health. Your body wants a stable, nutritious intake of nutrient-dense, unprocessed food prepared with adequate amounts of healthy oils and fats. Switching wildly from one extreme to the other, cutting out major foods groups, or relying on supplementation will definitely affect your health, if not your lifespan.
Second, the articles don’t distinguish between low-carb diets that strive for ketosis, and low-carb diets that focus on substitution of plant-based carbohydrates for processed carbs. Replacing carbohydrates, particularly processed carbohydrates, with plant-based proteins and healthy fats has been found to reduce the risk of mortality, albeit slightly. The authors of the study tell us that “the source of food notably modifies the association between carbohydrate intake and mortality” but this finding has been under-reported.
Lastly, although the study followed up 15,428 people for 25 years, the data covered only two years. The participants reported their eating habits between 1987 and 1989. I don’t need to remind you that self-report about food intake is always suspect. Moreover, the quality and nature of our food environment has changed fairly dramatically since the 80s.
What this study tells us is what we’ve been saying all along: Mortality varies by the source of macronutrients. You’re at higher risk when you exchange carbohydrates for animal-derived fat or protein and your risk decreases when your substitutions are plant-based.
Source: Seidelmann, Sara, et al. (8/18/2018) Dietary carbohydrate intake and mortality: A prospective cohort study and meta-analysis. The Lancet: Public Health. DOI: https://doi.org/10.1016/S2468-2667(18)30135-X