Month: May 2019

People who eat a low carb or ketogenic diet often ask about calculating “net carbs” and are surprised by my reply, as it differs from what they’ve read online. The commonly held advice is to subtract “fiber” from the total amount of carbohydrate on the label to arrive at “net carbs” can lead to an underestimation of nutrient intake, as well as possibly an underestimation of the effect of the food on blood glucose and insulin release when those foods are processed into other foods by grinding and/or heating.

As with other evidence-based meal patterns, a “whole foods” approach when following a low-carb lifestyle, is preferable. That doesn’t mean that people shouldn’t enjoy the occasional low-carb treat, as long as they understand that a baked good prepared from almond flour is not equivalent in terms of nutrient availability to the whole almonds from which it is made.

“Net Carbs” and the Perils of Food Processing

In a two-part series of articles posted in March 2018 on my dedicated low-carb website that were titled The Perils of Food Processing, I showed that both the amount and type of food processing applied to a food impacts the amount of nutrients available for absorption by the body, as well as having varying effects on the body’s insulin and blood sugar response. 

“Food processing” in this context means that amount that a food undergoes cutting or grinding and/or cooking in some way, including baking.

Mechanical processing, such pounding or grinding food is an ancient form of food processing which has an effect on how many nutrients are available to be digested. That is, the nutrients available to the body when food is eaten raw and whole versus raw and pounded is significant, and this holds true whether the food is animal protein such as meat or a starchy vegetable such as sweet potato. It is also true for foods such as almonds.

The availability of carbohydrate and energy is different for whole, raw almonds versus ground almonds such as almond flour — a staple in low carb and keto baking. More on that, below.

Changes in Insulin and Blood Glucose Response Resulting from Food Processing

As covered in the first article linked to above, mechanical processing of a food doesn’t change the amount of carbohydrate that is in it. That is, when we compare 60 g of whole apple with 60 g of pureed apple or 60 g of juiced apple, there is the same amount of carbohydrate in each. The Glycemic Index of these three are very similar so this isn’t very helpful to inform about the blood glucose response to actually eating these different foods.

When these foods are eaten, the insulin response and blood glucose response 90 minutes later is significantly  different.

As can be seen by the graph on the right, in healthy individuals blood insulin level goes very high with the juiced apple and in response, blood glucose then goes very low, below baseline. The response seen with the juiced apple is typical of what is seen with ultra-processed carbohydrates.

The same effect that is true for fruit is true when grain is ground; plasma insulin response increases the smaller the particle size of the grain.

Whole grain releases less insulin than the same amount of cracked grains, which is less than the same amount of course flour. The highest amount of insulin is released in response to eating the same amount of fine flour.

What is true for wheat is also true for rice and of interest, there isn’t a big difference between the insulin response with brown rice versus white rice.

While there is no difference in the Glycemic Index or Glycemic Load of whole wheat versus ground wheat or whole rice versus ground rice, there is a huge difference in the insulin response with difference types of mechanical processing.

Also as outlined in the previous articles (links above), the amount of fiber that was in the grain did not make a difference in the amount of insulin released, only the amount of mechanical processing of the grain. So, eating brown rice versus white rice won’t change the amount of insulin that is released.

Remember, insulin is a hormone that signals the body to store energy (calories), so increased insulin response in response to grinding food is important.

In short, it is the amount of cell disruption caused by grinding that increases insulin and glucose response; not the specific amount of carbohydrate in the whole food, nor the amount of fiber in the food.

For those with Type 2 Diabetes or pre-diabetes, applying “net carb” calculations to foods that have been ground is a problem; as it does not take into account the increased insulin release and resulting change in glucose response, as well as the change in energy availability caused by the grinding.

NOTE (June 2 2019): The fiber in the whole food and the ground food remains unchanged and is indigestible by the body, although it is digested by the gut microbiome into fatty acids. While fiber may slow the gastric emptying of the ground product (compared to the same product with the fiber removed), in and by itself the presence of fiber in the ground product compared to the whole food does not reduce the impact on insulin and glycemic response that the grinding causes. 

The Effect of Cooking on Nutrient Availability

Also as documented in the first of the two articles on food processing, cooking also has an effect on nutrient availability. When grains are cooked they become much more digestible — meaning that more of the nutrients are available to be absorbed. In the case of potatoes, there is double or triple the amount of energy (calories) available to the body when they are cooked versus when they are raw and these calories are now available to the body where they weren’t when they were raw.

When foods that are high in fat (lipid) such as peanuts are cooked, the amount of energy the body is able to derive from the food, increases.

Does Food Processing Affect Almonds?

Yesterday, in preparing to write this article, I was curious if there was any information available specifically about almonds as almond flour is used in most low-carb and “keto” baked goods. 

I went looking and found a September 2016 article in the International Journal of Food Science and Technology titled “A review of the impact of processing on nutrient bioaccessibility and digestion of almonds” [1] which documents the most common processing technique used on almonds and their effect on the digestion of nutrients.

In short, lab studies and animal and human studies demonstrate that there are marked differences in the way various forms of almonds (whole raw, whole roasted, blanched, milled flour) are digested and the amount of different macronutrients that are absorbed.

What is true with grinding grain, apples and peanuts holds true for almonds.

It is reasonable to assume that the body’s release of insulin and the corresponding glucose response is similarly changed by the increased bioavailablity of nutrients in those processed foods.

Ultra-processed foods, whether fruit, grains, or nuts are not treated by the body the same as whole, unprocessed foods. The macronutrient availability (i.e. amount of carbohydrate and energy) in whole, unprocessed foods is not the same as in the same foods that have been ground and/or heated, and the amount of insulin released and glucose absorbed can differ too.

Final Thoughts on “Net Carbs”

One cannot simply subtract the fiber that is contained in the whole, unprocessed food from the total carbohydrate content of the processed food and arrive at “net carbs” because the amount of macronutrient absorption of the food is increased due to the cell disruption of grinding and heating. For those with Type 2 Diabetes or pre-diabetes, one also needs to factor in the differential impact on insulin and blood glucose release that results from the food processing.

One can subtract the fiber in whole, raw almonds and arrive at “net carbs” on the assumption that the fiber is indigestible by the body and that the other nutrients listed on the label apply to the food in it’s current form, but roasting and grinding those same almonds into almond butter or grinding those almonds into almond flour and then baking (i.e. cooking) them into a host of low carb or keto ‘treats’ on the basis of their low “net carb” content can significantly underestimate their total macronutrient content. 

Should one choose to use the idea of “net carbs”, it should be applied only to whole, unprocessed (not ground or heated) foods.

Ultra-processed foods, irrespective of the carbohydrate content of the original whole, unprocessed foods from which they are made are not equivalent in nutrient availability or the body’s response to them as to whole, unprocessed foods.

While low-carb and keto ‘treats’ may be nice as “sometimes foods”, they are not ideal as “everyday foods” if weight loss and lowering blood glucose and insulin response are goals.

More Info?

If you would like to know more about following a low carbohydrate lifestyle or to adopt it for health reasons, I can help. You can learn more about my services under the Services tab or in the Shop.

If you have questions, please feel free to send me a note using the Contact Me form above and I will reply as soon as I can.

To your good health!

Joy

You can follow me on:

Twitter: https://twitter.com/lchfRD Facebook: https://www.facebook.com/BetterByDesignNutrition/
Instagram: https://www.instagram.com/lchf_rd

Copyright ©2019 BetterByDesign Nutrition Ltd.

LEGAL NOTICE: The contents of this blog, including text, images and cited statistics as well as all other material contained here (the ”content”) are for information purposes only.  The content is not intended to be a substitute for professional advice, medical diagnosis and/or treatment and is not suitable for self-administration without the knowledge of your physician and regular monitoring by your physician. Do not disregard medical advice and always consult your physician with any questions you may have regarding a medical condition or before implementing anything  you have read or heard in our content.

Reference

1. Grundy MM, Lapsley K, Ellis PR. A review of the impact of processing on nutrient bioaccessibility and digestion of almonds. Int J Food Sci Technol. 2016;51(9):1937—1946. doi:10.1111/ijfs.13192

Introduction

The infographic below has been making the rounds recently on social media and is based on the idea that high Glycemic Index (GI) foods can be represented by the effect those foods have on people’s blood sugar, compared to teaspoons of sugar.

Below is an infographic developed by Dr. David Unwin that describes the effect each food has on blood glucose based on the Glycemic Index [1], which is explained below. 

But can the effect of high Glycemic Index (GI) foods on blood glucose be accurately represented by the equivalent amount of teaspoons of sugar? The issue is that these tools are only as useful as the Glycemic Index (GI) is reliable.

The question is, is the Glycemic Index (GI) and Glycemic Load (GL), which is derived from it, reliable for predicting blood sugar response?

If Glycemic Index (GI) values

(1) change between individuals for the same amount of the same food, or

(2) change value within the same individual when they are assessed at different times

…then they cannot be relied on to predict blood sugar response in an individual.

That is what this article is about.

Glycemic Index (GI)

The Glycemic Index (GI) is a ranking system for carbohydrate-containing foods and is based on how quickly they raise blood sugar (blood glucose) levels after they are eaten.

Foods are ranked on a scale of 0 to 100, with pure glucose assigned a value of 100. 

High GI foods (ranked with a GI of 70 or more) are rapidly digested and absorbed, causing a quick and high spike in blood sugar levels.

Medium GI foods (ranked with a GI of 56-69) have a moderate effect on blood sugar levels.

Low GI foods (ranked with a GI of 55 or less) are digested and absorbed slowly, releasing glucose gradually into the bloodstream and causing a slower, smaller rise in blood sugar. 

The glycemic index of table sugar (which is sucrose) is rated with a GI of 65-80, depending on the source. 

Is Glycemic Index Reliable for Predicting Blood Sugar Response?

A study published in the American Journal of Clinical Nutrition [2] reported that individual responses to individual carbohydrate-containing foods vary so much that Glycemic Index values may not be useful in indicating blood sugar response in individuals.

The Study

Randomized, controlled, repeated tests on 63 healthy adults were conducted in 6 testing sessions over twelve weeks, and participants fasted and abstained from exercise and alcohol before each session.

During each session, participants ate either (1) white bread (test food) or (2) a standardized glucose drink (reference control).

Blood sugar values were measured at several points over the next 5 hours, and the Glycemic Index was derived by testing the test food and reference in the same participant according to the standard method. This is usual practice to control for the variability between people, which may be caused by biological differences.

Results

Out of the 63 participants, in 22 participants, blood sugar response was classified as “low”, in 23 participants it was classified as “medium”, and in 18 participants it was classified as “high’ for the same amount of bread.

That is, white bread fell in all three Glycemic Index categories with different individuals. In addition, responses within the same individual varied by as much as 60 points between tests.

Interpretation of the Results

The study indicated that blood glucose response is affected by the differing physical structure of similar foods, the effect of food processing and preparation methods, as well as meal consumption patterns (single or mixed meals).

The study authors concluded that the high inter- (between people) and intra-individual (within the same person) variation that was observed in the GI value of foods essentially resulted in the results being of no practical value.

“In summary, our data indicate substantial variability in GI value  determinations for white bread despite the use of standardized methodology and multiple testing in a large number of healthy volunteers. The high degree of variability demonstrates that there is potential to misclassify foods into the 3 commonly used GI categories (low, medium, and high), which would result in the inability to distinguish between foods, thus invalidating the practical applicability of the GI value.”

 

The authors also indicated that this variability was also partly explained by differences in baseline HbA1c (i.e., glycated hemoglobin), which is an estimate of 3 3-month average of blood glucose control, as well as the insulin index (the differing insulin response to foods), both affect the GI value.

Individual Glycemic Response

It should be noted that inter-individual and intra-individual variation in glycemic response isn’t only to white bread, as in the above small study.

A 2015 study from Israel [3] involving 800 people who were monitored with continuous glucose monitors (CGMs) found that (1) there isn’t a universal’ blood sugar response to either low Glycemic Index foods or high Glycemic Index foods, and that (2) glycemic (blood sugar) response is very individual.

“We continuously monitored week-long glucose levels in an 800-person cohort, measured responses to 46,898 meals, and found high variability in the response to identical meals, suggesting that universal dietary recommendations may have limited utility”.

Final Thoughts…

One cannot reliably predict that a specific amount of carbohydrate-based food will raise a person’s blood sugar the same amount as a certain number of teaspoons of sugar, because each carbohydrate-based food will have different effects on different people, and different effects within the same individual, at different points in time.

More Info?

If you would like to know how to determine how you respond to specific carbohydrate-based foods and how to know which carbohydrate-based foods spike your blood sugar and which don’t, I can help.

You can learn about my services under the Services tab.

To your good health!

Joy

You can follow me on:

Twitter: https://twitter.com/lchfRD
Facebook: https://www.facebook.com/BetterByDesignNutrition/
Instagram: https://www.instagram.com/lchf_rd

Copyright ©2019 BetterByDesign Nutrition Ltd.

LEGAL NOTICE: The contents of this blog, including text, images, and cited statistics, as well as all other material contained here (the ”content”) are for information purposes only.  The content is not intended to be a substitute for professional advice, medical diagnosis, and/or treatment, and is not suitable for self-administration without the knowledge of your physician and regular monitoring by your physician. Do not disregard medical advice and always consult your physician with any questions you may have regarding a medical condition or before implementing anything you have read or heard in our content.

Reference

1. Unwin D, Haslam D, Livesey G. It is the glycaemic response to, not the carbohydrate content of food that matters in diabetes and obesity: The glycaemic index revisited. Journal of Insulin Resistance. 2016;1(1), a8. http://dx.doi.org/10.4102/jir.v1i1.8
2. Matthan NR, Ausman LM, Meng H, Tighiouart H, Lichtenstein AH. Estimating the reliability of glycemic index values and potential sources of methodological and biological variability. Am J Clin Nutr. 2016;104(4):1004—1013. doi:10.3945/ajcn.116.137208
3. Zeevi D, Korem T, Zmora N, et al. Personalized Nutrition by Prediction of Glycemic Responses. Cell. 2015 Nov 19;163(5):1079-1094.

A new study published today in Preventive Medicine estimates that excess body weight, including overweight and obesity is expected to become the second leading cause of preventable cancer in Canada, after tobacco over the next 20 years.

Cancer Rates Expected to Triple

The results of the new ComPARe study (Canadian Population Attributable Risk of Cancer) stemming from research conducted by the Canadian Cancer Society and a Canadian team of experts in epidemiology, biostatistics, cancer risk factors, and cancer prevention provides estimates of the number and percentage of more than 30 cancer types in Canada. 

It found that if current trends continues, it is expected that new cancer cases related to overweight or obesity will triple over the next 20 years, from the current 7,200 cases per year to 21,200 cases per year. These figures are due to overweight and obesity alone and do not include the increase number of cancer cases that are expected due to smoking, physical inactivity / sitting too much or alcohol consumption.

Excess body weight increases the risk of esophageal and endometrial cancer by about 50% and increases the risk of kidney, gallbladder, stomach and liver cancers by 20-30%.  Achieving and maintaining a healthy body weight can substantially lower the risk of these, and other cancers. The study estimates that if Canadians maintained a healthy body weight (BMI ⩽  25), that approximately 110,600 cancer cases could be prevented by the year 2042.

UPDATED (May 8, 2019 5:00 PM): It is not body weight per se that increases the risk of cancer. There are several proposed mechanisms where excess body weight may increase cancer risk, including alterations in the levels of hormones and growth factors, chronic inflammation, excess insulin and leptin. It is thought that excess insulin may help promote cancer cell growth and cause insulin resistance, which
increases the risk of colon, endometrial and kidney cancers in particular.

If you’d like to know how I can help you with symptoms of overweight or obesity (or some of the metabolic disorders that often accompany them), please let me know.

You can learn more about my services and their costs above under the Services tab or in the Shop and if you have questions, please feel free to send me a note using the Contact Me form above and I will reply as soon as I can.

To our good health!

Joy

You can follow me on:

Twitter: https://twitter.com/lchfRD
Facebook: https://www.facebook.com/BetterByDesignNutrition/
Instagram: https://www.instagram.com/lchf_rd

Copyright BetterByDesign Nutrition Ltd.

LEGAL NOTICE: The contents of this blog, including text, images and cited statistics as well as all other material contained here (the ”content”) are for information purposes only.  The content is not intended to be a substitute for professional advice, medical diagnosis and/or treatment and is not suitable for self-administration without the knowledge of your physician and regular monitoring by your physician. Do not disregard medical advice and always consult your physician with any questions you may have regarding a medical condition or before implementing anything  you have read or heard in our content.

In its recently published Consensus Report (April 18, 2019), the American Diabetes Association confirmed something that I have written about in several previous articles, including most recently in Part III of Carbohydrates are Not Evil and that is that it isn’t biologically essential to eat carbohydrate containing foods in the diet. From the top of page 4 of the Consensus Report:

“The amount of carbohydrate intake required for optimal health in humans is unknown. Although the recommended dietary allowance for carbohydrate for adults without diabetes (19 years and older) is 130 g/day and is determined in part by the brain’s requirement for glucose, this energy requirement can be fulfilled by the body’s metabolic processes, which include glycogenolysis, gluconeogenesis (via metabolism of the glycerol component of fat or gluconeogenic amino acids in protein), and/or ketogenesis in the setting of very low dietary carbohydrate intake.”

That is, the body can make all the glucose the brain needs from the glycogenolysis (which is the breakdown of glycogen to glucose), via  gluconeogenesis (which is the generation of glucose from glycerol or glucogenic amino acids) and via ketogenesis(which is from ketones generated in a very low dietary carbohydrate [ketogenic] diet). In short, dietary intake of carbohydrate is not essential. While there is no biological need to eat carbohydrate-based food, one certainly can and there are many good reasons to include some types of carbohydrate-containing food in the diet.

Because there is no essential need to eat carbohydrate because the body can make all the glucose it needs itself, the American Diabetes Association includes among its eating patterns both a low carbohydrate pattern (26-45% daily calories as carbohydrate) and a very low carbohydrate (ketogenic) eating pattern (20-50 g carbohydrate / day). How much carbohydrate is a major consideration for those who are pre-diabetic or Diabetic because as the ADA stated in this new consensus report;

“Carbohydrate is a readily used source of energy and the primary dietary influence on postprandial blood glucose.

That is, it is the carbohydrate in a meal that is the biggest predictor of how high blood sugar will rise after a meal, and how quickly. For those who want to improve their blood sugar levels (glycemia) the same report also makes it clear that;

“Reducing overall carbohydrate intake for individuals with diabetes has demonstrated the most evidence for improving glycemia* and may be applied in a variety of eating patterns that meet individual needs and preferences.”

For those adults with Type 2 Diabetes who are not meeting their blood sugar targets or who need to, or want to have their physician reduce their need for Diabetes medications, a low carbohydrate or very low carbohydrate (keto) eating pattern is a viable option;

“For select adults with type 2 diabetes not meeting glycemic targets or where reducing anti-glycemic medications is a priority, reducing overall carbohydrate intake with low or very low- carbohydrate eating plans is a viable approach.”

Remember, carbohydrate-based foods are not necessary for your brain because your body can make all the glucose it needs from the metabolic processes listed above. That’s not to say one has to avoid carbohydrate-based foods, but how much and how often can and is best determined based on people’s individual needs and glycemic response to carb-based foods.  I recently outlined in another article based on the American Diabetes Association’s Consensus Report and which was posted on my affiliated low carbohydrate-focused website, that in the US a well-designed low carb or ketogenic diet to lower blood sugar need not have all the same foods or food groups as a diet based on The Dietary Guidelines for Americans because it is used as Medical Nutrition Therapy (i.e. is a therapeutic diet).

While these are the guidelines in the US, in Canada individuals have the right to choose a low carbohydrate lifestyle if that is their personal preference.

If you would like some professional support to begin eating this way or to continue eating this way,  I can help. I provide Registered Dietitian services to those in any province in Canada (except PEI), and for those in the US, I can provide nutrition education to help you know how to eat according to a low carb eating pattern.

You can learn more about my services including individual hourly appointments and sessions as well as packages above under the Services tab or in the Shop and if you have questions, please feel free to send me a note using the Contact Me form above and I will reply as soon as I can.

To your good health!

Joy

Here are the links to other articles that I wrote about the new ADA Consensus Report:

April 24, 2019 – ADA Eating Patterns Differ from The Dietary Guidelines for Americans April 23, 2019 –  ADA includes use of a Very Low Carb (Keto) Eating Pattern in New Report

You can follow me on:

Twitter: https://twitter.com/lchfRD
Facebook: https://www.facebook.com/lchfRD/
Instagram: https://www.instagram.com/lchf_rd

Reference

Evert, AB, Dennison M, Gardner CD, et al, Nutrition Therapy for Adults With Diabetes or Prediabetes: A Consensus Report, Diabetes Care, Ahead of Print, published online April 18, 2019, https://doi.org/10.2337/dci19-0014 Copyright

©2019 The LCHF-Dietitian (a division of BetterByDesign Nutrition Ltd.)

LEGAL NOTICE: The contents of this blog, including text, images and cited statistics as well as all other material contained here (the ”content”) are for information purposes only.  The content is not intended to be a substitute for professional advice, medical diagnosis and/or treatment and is not suitable for self-administration without the knowledge of your physician and regular monitoring by your physician. Do not disregard medical advice and always consult your physician with any questions you may have regarding a medical condition or before implementing anything  you have read or heard in our content.