It seems like there has been a great deal of interest in the macronutrient change from 1.3 to 1.4. In case anyone is interested, we decided to discuss the scientific rationale behind the change and why it helps make the best version of Soylent yet. I’ve pasted a version of the discussion below, however to see the complete list of footnotes and citations, head over to the FAQ page.
Keep on asking great questions!
One of the biggest changes in 1.4 was the readjusted macronutrient energy ratio - commonly referred to as just the macronutrient ratio.
In Soylent versions 1.3 and earlier, the energy was divided as follows: 50 percent of calories from carbohydrates, 30 percent of calories from fats and 20 percent of calories from protein. Alternatively, this could be written as a macronutrient ratio of 50/30/20.
In version 1.4, the ratio was adjusted to 43 percent of calories from carbohydrates, 40 percent of calories from fats and 17 percent of calories from protein, or 43/40/17.
The data from internal tests showed that the reduction of protein, specifically from 114 grams per pouch in 1.3, to 84 grams per pouch in 1.4 resulted in greatly improved digestibility. Furthermore, the increase in unsaturated fats allowed for a more even release of energy.
Finding the perfect macronutrient ratio is a balance between the best mix of short- and long-term energy. Too much short-term energy - provided via simple carbohydrates - can cause one to experience an energy “rush” and subsequent “crash”.
In contrast, too much long-term energy, via lipids (primarily fats) and proteins, can leave one feeling tired for several hours after digestion, until the body is able to harvest energy from slow-metabolizing fats and proteins.
Historic studies have suggested positive correlations between fat consumption and coronary heart disease. Modern science, however, has tweaked this definition to instead focus on the correlation between saturated fat consumption and coronary heart disease.
The Institute of Medicine’s Food and Nutrition Board recommends that fats account for 25 to 35 percent of total energy intake. However, the Food and Nutrition Board notes that the upper limit is designed to prevent over-consumption of saturated fats.
Saturated fats are linked to increases in low-density lipoprotein cholesterol, which is positively associated with increased risk of cardiovascular disease. Specifically, saturated fats have been shown to block the expression of LDL receptors, which ultimately prevents this unhealthy type of cholesterol from being filtered out of the bloodstream.
In February, the annual report published by the USDA’s Dietary Guidelines Advisory Committee, further examined the significant health differences between saturated and unsaturated fats.
The report conducted a statistical review of four published meta-analyses, which in turn evaluated dozens of clinical trials of hundreds of thousands patients. The Dietary Guidelines Advisory Committee’s analysis found that for every 1 percent of energy intake of saturated fats that was replaced by an equivalent amount of polyunsaturated fats, the number of cases of coronary heart disease was reduced by 2 to 3 percent. (A review of the different types of fats in Soylent can be found here.)
This conclusion is in line with significant quantities of evidence which show that unsaturated fats, unlike saturated fats, do not increase LDL cholesterol concentrations in the bloodstream.
Soylent is a new type of food that is designed to have modular ingredients that only contribute to primarily one or two nutrient levels. As such, it is possible to provide a macronutrient energy ratio that is 40 percent energy due to fat, without the negative health effects of saturated fat. Ultimately, this results in the healthiest, best-tasting blend of Soylent yet.