The Sweet Spot

The blog post Low Carb Diets Unsafe looks at up to date research into the effects of eating a low carb diet in the long term. However, that does not mean eating a high carbohydrate diet is the way to go. And what constitutes a high carb diet anyway?

According to new research published in The Lancet Public Health journal eating carbohydrates in moderation seems to be optimal for health and longevity.

The study of more than 15,000 people in the USA found that diets both low (< 40% energy) and high (>70% energy) in carbohydrates were linked with an increase in mortality, while those eating a moderate amount of carbohydrates (50-55% of energy) had the lowest risk of mortality (1).

Further, a meta-analysis of studies on carbohydrate intake including more than 400,000 people from over 20 countries, also found that not all low-carbohydrate diets appear equal. Eating more animal proteins and fats such as beef, lamb, pork, chicken and cheese, instead of carbohydrate was associated with a greater risk of mortality. Alternatively, eating more plant proteins and fats from foods such as vegetables, beans, lentils, and nuts was linked to lower mortality.

Low carb diets can aid weight loss in the short term and may improve some cardiometabolic risk factors. But following a low carb diet in the long term is controversial with studies producing conflicting results.

Low carb diets tend to be lower in fruit, vegetables and grains and higher in animal proteins and fats which may be implicated in inflammation and oxidative stress which could explain the increase in mortality in those eating low carb diets. 

On the other hand high carb diets common in less economically advantaged nations tend to be high in refined carbohydrates such as white rice. This may be contributing to the higher mortality rate in this group.

Future Research Needs

The different effects of animal protein versus plant protein, saturated fats and processed fats versus essential fats, and complex carbs versus refined carbs need to be taken into account as their effects on health are likely to be wildly different.

Conclusion

In the long term it seems that too much or too little carbohydrate is not ideal. For most people in a reasonable state of health a moderate intake of slow releasing carbohydrate around 50% of energy seems like a good option. If one decides to go low carb for a period of time it may be advisable to swap the carbs for plant based fats and proteins rather than animal products.

References

1. 1.Sara B Seidelmann, Brian Claggett, Susan Cheng, Mir Henglin, Amil Shah, Lyn M Steffen, Aaron R Folsom, Eric B Rimm, Walter C Willett, Scott D Solomon. Dietary carbohydrate intake and mortality: a prospective cohort study and meta-analysis. The Lancet Public Health, 2018;