Calories, Carbs, Quality, and Obesity

For decades now, we’ve been debating the role of macronutrients in weight gain. But that fierce debate has yielded precious little consensus. Low-fat dietary guidance ruled the land for decades. Right now, low-carb diets seem to have the upper hand. However, in a new webinar, Kevin Hall suggests that neither calories, carbs, nor fat tell that whole story – rather it’s the quality of the food that counts.

The Latest in a Series of Rigorous Studies

Hall walks us through a series of well controlled studies that serve to question a lot of conventional wisdom about diet and weight. He suggests that the carbohydrate-insulin model does not hold up to rigorous scientific testing. This model provides the scientific rationale for thinking that cutting carbs might be a good strategy for getting obesity under control.

But in Hall’s latest study, people actually tended to eat more calories on a low-carb diet and thus lose more weight on a low fat diet. Of course, this study was short-term and longer-term studies have generally found similar results from these two dietary strategies. However you slice it, though, it’s pretty hard to say that one approach is superior to the other. Different people get different results.

Food Quality Above All?

And that brings Hall back to the possibility that it’s quality – not carbs, fat, or calories – that matters most. As obesity has risen, the consumption of ultra-processed foods has risen, too.

To support his proposition that it’s food quality that matters most, Hall points to a carefully controlled study of ultra-processed versus unprocessed foods. The study demonstrated that the ultra-processed foods did indeed cause significant weight gain in just two weeks.

At the end of all this we are left with more questions than ever. Some questions relate to the squishy definition of ultra-processed foods. Other questions are all about understanding what the longer-term outcomes might be with these food quality issues. The foods we eat are quite complex and the great variety in foods means that studying our diets is even more complex.

A person can eat healthfully in many different ways. So we have much to learn about the factors in our food and our diets that are driving obesity.

If you want to learn more, we strongly recommend that you click here for Hall’s webinar. It requires registration, but it’s free, available on demand, and quite rewarding to watch.

Bröd, photograph © Jonas Tana / flickr

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July 6, 2020

One Response to “Calories, Carbs, Quality, and Obesity”

  1. July 06, 2020 at 10:03 am, Allen Browne said:


    The key sentence may be – “different people get different results”. We struggle for a single, simple answer for all, but the scientists say it is complicated. It is probably not the disease of obesity but the diseases of obesity or the obesities.

    There are many ways to mess up the energy regulatory system and end up with a body composition that is not healthy. I suggest we respect complexity and find our how to tell who is who. No plots of average responses but plots that show each person’s response – histograms – and then start looking at groups with similar responses. More complicated but respectful of reality – each person is unique.

    Stay well.