The low carbohydrate has become a popular diet today however I will draw your attention to some “Thinking points” you should consider when reading this article that is posted above.
Firstly the attached article has an author who has a personal and financial interest in the promotion of a low carbohydrate diet. She is already selling books and diet plans she has authored on this topic which suggests bias cannot be ruled out. Secondly the studies used to support this diet are short term with low number of participants which we term “ Proof of Concept Studies”. Even the study attached highlights that there is no long-term randomised controlled trials (RCT) being the gold standard done in this area to prove this “proof of concept” yet. Healthcare professionals who treat are not interested in 6 month interventions but what can improve health long term.
A: There is no consensus on what a low carbohydrate diet is yet everyone talks about them as if they are all the same. There are enormous nutritional differences.
So what is a low carbohydrate diet? It can be as low as 20gm/carbs a day which means you cannot eat any fruit and vegetables let alone dairy products, beans or legumes in a day. Or a low carb diet can just mean no bread, sugar, potatoes or starch vegetables, rice or pasta .Or it can mean less than 40%Energy from carbs which is about 200gm carbs on a 2000Kcal/day diet which has a greater scope to include more foods that contain carbohydrate. Remember carbohydrate is also found in fruit, vegetables, dairy products, beans and legumes and most well known cereal grains. Dietary recommendations for peoples with T2 diabetes is around 45-60% of energy from carbohydrate choosing good quality carbohydrate to meet many different lifestyle and nutritional needs.
Each of these diets described above are quite different nutritionally from each other, so we cannot assume they are the same when it comes to health benefits. The article attached in the post above stated that before the obesity crisis most Americans were eating around 43% of their energy as carbohydrates. Interestingly they also say the average carbohydrate intake in Americans today with the obesity crisis is around 49% of energy. As we can see there is very little difference. So this tells us there is something more about this story not to mention lifestyle.
B: Most studies on high carbohydrate diets do not determine the quality of carbohydrate. So we cannot rule out that the majority of carbohydrate may have been coming from processed carbohydrate foods like pasta, rice, breakfast cereals breads, muffins, muesli bars and sugar sweetened beverages (SSB) etc. If the high carbohydrate diet came from foods like fresh whole fruit and vegetables, dairy products and dried beans, legumes and lentils is it better? We do not know as we do not have this research though it is partly addressed by the Mediterranean Diet and the glycaemic index. So we cannot talk about carbohydrate without talking about the food and the form in which the carbohydrate is being eaten.
C: If a diet is low in carbohydrate then it is high in something else. This is usually FAT. We know that a diet high in processed carbohydrate eg SSB is as bad as a diet high in fat. What we don't have is RCT showing differences in a diet high in more intact carbohydrate like whole fresh fruit, vegetables, dried beans , legumes, lentils, different cereal grains ( quinoa, oats etc) dairy products compared to proceesed carbohydrates and high fat diets. However the Mediterranean diet suggests to us quality carbohydrate, high fruit and vegetables, dairy products might be just the way to go.
D: Already mentioned the diet plan that consistently comes up trumps is the Mediterranean diet which is neither low carbohydrate or high fat. This diet addresses quality by talking food not nutrients and has been around for a very long time with some great health outcomes.
E: Those advocating less than 100- 120g/day of carbohydrate will be at of risk of having inadequate fresh fruit and vegetables, insufficient fibre especially soluble fibre required for a healthy gut and insufficient dietary calcium.
Maybe consider a much longer term study than that used in the article attached- a prospective cohort study ( not a RCT) of 82,802 US nurses over 19 years, reported that a low-carbohydrate dietary pattern that emphasizing animal sources of fat and protein was associated with a higher risk of type 2 diabetes mellitus and all-cause mortality. In contrast a low-carbohydrate diet that emphasizing high intakes of vegetable protein and unsaturated fat was associated with a lower risk of coronary heart disease over 19 years of follow-up. The investigators also found this pattern was associated with a lower risk of cardiovascular and all-cause mortality among both men and women.
We need to stop talking nutrients and start talking FOOD.