Gucci vs. Gap carbs

Generally made up of sugars, starches, and dietary fiber^[1], carbohydrate-containing foods are a prominent source of dietary energy worldwide. However, there have been reports as early as 1969^[2] warning about associations between refined carbohydrate and chronic disease. Now, recommendations embrace a 45%-65% range^[3] of total energy from carbohydrate, with sugar making up less than 10% of total energy^[4] in the overall diet.

Indeed, studies^[5] have demonstrated that an excessive consumption of calorically dense and micronutrient-poor foods, or “empty calories,” that are generally found at a convenience store^[6], are associated with various cardiometabolic complications such as coronary heart disease^[7], stroke^[8], and type 2 diabetes^[9]. However, researchers have also started to understand how carbohydrate-containing foods may not be all that bad when whole. As you can see in Figure 1, the processing^[10] to achieve a refined grain removes several healthful components (especially dietary fiber), turning this staple into a demon—transforming the whole grain into an “empty” grain.

This has become even more relevant as the benefits of different components of carbohydrates are revealed, raising the question of whether different carbohydrate components might serve as markers of carbohydrate quality in the overall context of a diet. Dietary fiber is one component in particular that has demonstrated modest beneficial influence on satiety^[11], appetite, and blood lipids^[12]. While dietary fiber is a kind of carbohydrate that can’t be digested by our body’s enzymes, the ‘good’ microbiota in our guts feed on them and appear to be driving some of the potential benefits^[13] attributed to dietary fiber. Beside that indigestible part of our diet, whole grains^[14] also carry phytochemicals, such as carotenoids and polyphenols, and vitamin E that exhibit antioxidant potential and have been associated with reductions in inflammation^[15] and chronic disease^[16].

Previous studies^[17][18] have demonstrated positive associations between health and diets characterized by higher markers of carbohydrate quality. However, these studies only explored a single aspect of carbohydrate quality (e.g., whole grain intake) and a limited number of clinical outcomes. This makes it difficult to determine how useful markers of carbohydrate quality are for predicting their potential for chronic disease prevention. The authors of the study under review aimed to quantify the predictive potential of several markers for carbohydrate quality and determine which might be most useful to predict chronic disease mortality and risk. A particular focus was placed on dietary fiber and deriving a quantitative recommendation for its intake. For this purpose, the researchers used data from both prospective studies and randomized controlled trials (RCTs) to quantify and ideally bridge the gap between experimental and observational data.

Carbohydrates are a staple of the human diet. Types of dietary carbohydrates include sugars, starches, and dietary fiber. Excessive processing of whole sources of carbohydrates might be stripping the foods of components that might improve their quality by making them healthier. Whole grains and dietary fiber have been associated with various benefits, including associations with reduced chronic disease, but previous studies have only investigated single markers of carbohydrate quality and a limited number of clinical outcomes. The authors of the study under review aimed to quantify and compare the predictive potential of several markers of carbohydrate quality for chronic disease mortality and risk based on data from both observational and experimental data.