Just Read: Assessing the nutrient intake of a low-carbohydrate, high-fat (LCHF) diet

This paper asks an interesting question that feels like a subtext of so many other papers – Why do people express fear of an LCHF (low carbohydrate, healthy fat) diet? Which, according to Google trends, is winning in mindshare.

It’s written by Caryn Zinn (@CarynZinn), Amy Rush, and Rebecca Johnson (@type_oneder), the CEO of Telethon Type 1 Family Centre in Australia

LCHF continues to remain a highly contentious topic in nutrition circles. Two likely reasons for this are as follows: (1) the supposition that LCHF diets are devoid of certain nutrients, and therefore increase risk of nutrient deficiencies and (2) concern around the saturated fat content of the diets and the speculation that high intakes might increase risk of cardiovascular disease.Zinn C, Rush A, Johnson R. Assessing the nutrient intake of a low-carbohydrate, high-fat (LCHF) diet: a hypothetical case study design. BMJ Open [Internet]. 2018 Feb 8;8(2):e018846.

The approach, then, to describe what a meal plan with an LCHF diet looks like, both in a version with a 10% saturated fat limit and one without, for men and women.

A few myths and differences revealed

The LCHF nutrition approach tends not to exclude any food groups specifically but rather focuses on reducing intake from high-load carbohydrate foods in general; and when carbohydrate is eaten, whole-food sources are preferred to processed ones.Zinn C, Rush A, Johnson R. Assessing the nutrient intake of a low-carbohydrate, high-fat (LCHF) diet: a hypothetical case study design. BMJ Open [Internet]. 2018 Feb 8;8(2):e018846.

This is a departure from what people say is “Atkins” in that

  • It’s not a high protein diet
  • Focus is on real foods

Other difference I would add is the caliber of scientists in this space (much more credentialed in their fields) in this century.

Despite the known nutrient deficiency risks that arise with vegan and some vegetarian eating styles, national and international nutrition organisations are not dissuasive of these diets; nutrition professionals merely address any dietary issues in clinical practice.19 20 By contrast, carbohydrate-restricted diets are still frowned on by many dietitians and associated national organisations,10 despite their endorsement by some organisations such as the Commonwealth Scientific and Industrial Research OrganisationZinn C, Rush A, Johnson R. Assessing the nutrient intake of a low-carbohydrate, high-fat (LCHF) diet: a hypothetical case study design. BMJ Open [Internet]. 2018 Feb 8;8(2):e018846.

CSIRO is the Australian version of the NIH, and indeed, they are engaged in reformulating diets for diabetes prevention and reversal: Improved diabetes control with new diet – CSIRO

The diets

They are laid out in tables in the paper. The low carbohydrate threshold here is 130 grams a day.

It’s useful to eyeball what the < 10% saturated fat looks like compared to the non saturated fat restricted diet. To my eyes, the lower saturated fat diet would be less appealing/satiating to some.

Also, a reminder that there are only so many micronutrients that can be eaten – I have observed medical professionals not realize that a “low-fat” diet is the same as a “high-carbohydrate” one, keeping protein constant.

To achieve carbohydrate and protein targets, the only way to achieve the energy requirements with a less than 10 % saturated fat threshold was to add an alcoholic beverage into the meal plan, as it is the only food item that provides energy without any other macronutrient. We viewed this as being somewhat futile so decided against this option.Zinn C, Rush A, Johnson R. Assessing the nutrient intake of a low-carbohydrate, high-fat (LCHF) diet: a hypothetical case study design. BMJ Open [Internet]. 2018 Feb 8;8(2):e018846.

I’ve touched on saturated fat separately on this blog, specifically that most saturated fat in the SAD (standard American diet) comes from processed foods, and the evidence of its harm is rapidly (or has been?) deconstructed.

Watch the bean and seed oils

A key characteristic of the LCHF way of eating is the discouragement of consumption of seed oils (eg, canola, sunflower, soybean, corn oil and rice bran oil) to minimise intake of linoleic acid (omega-6 PUFA), and consequently, to achieve an optimal omega-6:omega-3 ratio.Zinn C, Rush A, Johnson R. Assessing the nutrient intake of a low-carbohydrate, high-fat (LCHF) diet: a hypothetical case study design. BMJ Open [Internet]. 2018 Feb 8;8(2):e018846.

Conclusion

I overall like the approach here, which is more about what’s available rather than what’s restricted. I learned about this work from hearing Bec’s story as a type 1 diabetic and the work she does with kids to be able to live their lives in optimal health with diabetes.

If there’s a theme of the things I have been learning recently, it’s the challenges to achieving life goals imposed by diabetes, in many ways never fully explained in medical training, and in other ways, very relevant and congruent to life as an LGBTQ human working to live and achieve their life goals as their authentic selves. It’s all related…

Zinn C, Rush A, Johnson R. Assessing the nutrient intake of a low-carbohydrate, high-fat (LCHF) diet: a hypothetical case study design. BMJ Open [Internet]. 2018 Feb 8;8(2):e018846.

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