Maybe carbohydrates aren’t that bad after all

Julia Belloz at Vox – We’ve long blamed carbs for making us fat. What if that’s wrong?

The main scientific model behind the low-carb approach is the “carbohydrate-insulin hypothesis,” which journalist Gary Taubes, Harvard professor David Ludwig, and others have extensively promoted. It suggests that a diet heavy in carbohydrates (especially refined grains and sugars) leads to weight gain because of a specific mechanism: Carbs drive up insulin in the body, causing the body to hold on to fat and suppress calorie burn.

But what’s often lost in all the boosterism around the low-carb approach is that it is still an unproven hypothesis in science.

So they did a study to show whether a low-carb diet can actually help to reduce weight. 17 overweight or obese men in a metabolic chamber for 4 weeks and fed either a high carbohydrate diet or ketogenic diet with the same number of calories. Results? No increased body fat loss with the ketogenic diet.

But as Bazinet points out, “The study … doesn’t see any [relationship between a decrease in insulin and an increase in fat loss]. Show me a better study that supports this.”

There isn’t any, he added.

Ah. Conclusions?

Tobias urged dieters not to lose sight of the bigger picture. “Low-carb versus low-fat should not be the focus for people selecting a weight loss diet.” The focus, she said, should be on improving the quality of food that people eat instead.

On Fat and Sugar

Jill Eisen for the CBC – Fat and Sugar, Part 1

First, fat was the dietary bad guy. We were warned back in the 1980s to cut back on eggs, meat and full-fat dairy to avoid heart disease. So we started eating more bread, rice and pasta and fat-free snacks. But we got sicker and fatter. Now sugar is the bad guy. Contributor Jill Eisen explores the complex, and sometimes contradictory, science of nutrition — and tries to find clarity amidst the thicket of studies and ambiguous research.

There’s also a great list of research references and a reading list at the link, for more information.

Part 2 airs on June 22, 2016.

Healthy and overweight?

A doctor and a professor discuss – Are there health benefits to being overweight?

Carl J. Lavie:

The good news for those who may be struggling to lose weight and keep it off is this: As I explored in my book “The Obesity Paradox,” there can be surprising benefits to carrying around a few extra pounds. In fact, being out of physical shape and having low overall fitness is actually a far greater danger to health than fat, especially in people who are only slightly overweight.

Andrew Stokes:

Using information on weight history, it is possible to address this seemingly intractable source of bias. Weight history makes it possible to distinguish people who were slim throughout their lives from those who were formerly overweight or obese but lost weight.

In other words, Stokes is claiming that most studies include weight at the start of the study and throughout the study, but neglect the weight history of the person. The formerly overweight/obese who were ‘normal’ weight at the time of the study may have higher mortality due to issues related to the former excess weight, and therefore skew the results to look like overweight people have lower mortality (as a group). Interesting.

The study by Stokes and Preston goes into further depth on the weight history theory. The conclusions are stark (emphasis mine) :

Our results suggest the burden of overweight and obesity on mortality is likely substantially larger than commonly appreciated. If correct, this may have serious implications for the future of life expectancy in the United States. Although the prevalence of obesity may level off or even decline, the history of rapidly rising obesity in the last 3 decades cannot be readily erased (63). Successive birth cohorts embody heavier and heavier obesity histories, regardless of current levels. Those histories are likely to exert upward pressure on US mortality levels for many years to come.

Canadian Senate report on obesity – first thoughts

The Canadian Senate report – Obesity in Canada – A While-of-Society Approach for a Healthier Canada was released last week:

There is an obesity crisis in this country. Canadians are paying for it with their wallets — and with their lives.

Harsh and sobering. The infographic is good.

Among the more controversial recommendations:

  • Consider a tax on sugar- and artificially-sweetened drinks
  • Ban the advertising of food and beverages to children
  • Immediately update the food guide without industry influence

Sugar Tax?

The Canadian Taxpayer Federation and the Canadian Beverage Association both denounce the recommended sugar tax, claiming that it doesn’t work. Three comments:

  1. The discussion and promotion of such a tax is very helpful and brings some awareness to the issue of high sugar consumption, whether the tax is implemented or not.
  2. We need to look at the sugar content of all processed foods and see if such a tax should be expanded to cover foods with added sugars/sweeteners, natural or artificial. Even foods such as fruit juices, which give us the liquid without any of the fibre of the fruit, need to be reviewed for inclusion.
  3. As with salt, we need guidelines on the recommended maximum daily intake of added sugars, and the report suggests this in the text.

The CBC hosted a short forum discussion on the sugar tax last week.

Restricting food advertising to children

As for advertising, currently the Quebec Consumer Protections Act protects children (under the age of 13) from any commercial advertising:

248. Subject to what is provided in the regulations, no person may make use of commercial advertising directed at persons under thirteen years of age.

1978, c. 9, s. 248.

249. To determine whether or not an advertisement is directed at persons under thirteen years of age, account must be taken of the context of its presentation, and in particular of

(a) the nature and intended purpose of the goods advertised;
(b) the manner of presenting such advertisement;

(c) the time and place it is shown.

The fact that such advertisement may be contained in printed matter intended for persons thirteen years of age and over or intended both for persons under thirteen years of age and for persons thirteen years of age and over, or that it may be broadcast during air time intended for persons thirteen years of age and over or intended both for persons under thirteen years of age and for persons thirteen years of age and over does not create a presumption that it is not directed at persons under thirteen years of age.
1978, c. 9, s. 249.
The Senate report calls for a study on the effects of this restriction in Quebec, and for implementation of a similar restriction for all of Canada.

Updating the food guide

The call for updating the food without industry influence is fantastic. I’m not sure how realistic this could be, since many non-industry researchers in academia are funded by industry, so does this mean they can’t be involved? The removal of politics from the food guide is one of the questions I’ve always had, in light of the huge ‘push’ for milk/dairy products as our main recommended calcium intake method.