Reacción a "The ketogenic diet may be more beneficial in the short term than other diets for people with obesity, according to a small clinical trial"

This study is significant because it uses a design that allows differences in the measured health markers to be attributed to the type of diet followed by the study participants. Although it is not stated whether the level of physical activity was similar across the groups of participants being compared – which could have affected the results had it differed between the comparison groups – the rest of the information regarding the study appears to be well-conducted. In the published study, it appears that all the diets compared included foods with a fairly healthy nutritional composition; therefore, the findings suggest that diets with a higher proportion of fat may be more beneficial for people who are overweight.

However, this study does not address the major issue with high-fat diets, which relates to their quality. It is not the same to follow a diet consisting mainly of foods high in unhealthy fats – such as those found in high-fat meats and processed foods – as it is to follow a diet comprising foods high in healthy fats, such as those found in olive oil and oily fish. Furthermore, high-carbohydrate diets may include healthy foods, such as whole grains, fruit and vegetables, and pulses, but they may also include foods that provide sugars – which are low-quality carbohydrates – such as sugary drinks or industrially produced pastries.

Our group recently published a study in which we found that a diet defined by its percentage of total fat or carbohydrates did not predict the risk of developing chronic diseases later in life. However, when this diet was defined by its quality – whether healthy or unhealthy, depending on the type of fats or carbohydrates consumed – people who followed unhealthy diets had a higher risk, of up to 11 per cent, of developing various diseases over the years.

The Spanish dietary guidelines recommend a diet that includes a moderate to high intake of healthy fats and a similarly moderate to high intake of healthy carbohydrates (adjusting the ratio depending on individual preferences or circumstances), alongside a moderate intake of animal protein and a high intake of plant-based protein. This combination appears to be the most balanced for preventing disease in the general population.