Setting Carb Intake Based on Insulin Tolerance

This is a contributed post by Mark Nazzal with

I’d be surprised if, at one point or another, you didn’t spend at least a few minutes wondering how much carbohydrates your diet should contain. Proteins and fats are pretty straightforward most of the time, but carbs? Tons of info, and you never really know what to believe.

I am, however, more interested in body composition than health benefits. So whatever you read from this point onwards, know that I have written it without giving inflammation and other such trendy topics a second glance. I’m only concerned with how appropriate carb intakes can influence our physical appearance.

Monitor carb intake for healthy weight loss

With that introduction behind us, here is my goal in writing this article: to make sure that you are capable of leveraging your current level of insulin resistance to your own advantage, as far as weight loss is concerned. No more, no less.

So without much time-wasting, let’s get to the point.

Are You Insulin-Resistant Or Insulin-Sensitive?

Our first order of business is actually figuring out what your current level of insulin tolerance is. Now, I should tell you that the only way to get an accurate result is to have blood tests performed in a specialized clinic, with the goal of measuring your insulin levels before and after different meals. This is the only real way to know what’s going on in your body.

I’m going to assume, however, that the above is not very practical for you, and so here’s another way you can figure it out for yourself without having to leave your house (providing you have some solid carbs over there, otherwise a trip to the grocery store is necessary).

Here is what I want you to do: prepare a carb-rich meal. My suggestion is either some sort of pasta, or a few really big sandwiches. Just make sure that it contains no less than 70 grams of simple carbs. Make sure a minimum of 4 hours have passed since the last meal you consumed, at which point you should eat your high-carb meal as quickly as possible.

And make sure that you don’t do anything taxing after consuming that meal. No physical exercise or anything of the sort. Actually, I want you to stay in front of the computer or watch TV for a minimum of 60 minutes after you finish your carb-rich meal. Once that hour is over, take note of the way you feel:

  1. Do you have a lot of energy and feel like you could do something demanding? If so, then you are quite likely insulin-sensitive.
  2. Do you feel a little sleepy, maybe even hungry already, despite having eaten that big meal? Perhaps with a particular craving for sweets? If so, then you are quite likely insulin-resistant.

The test above obviously isn’t a sure-fire way of measure things, however I have found that it’s almost always enough to give you an estimate of your insulin tolerance levels.

Once you are done with this part, let’s see how we can set up your carbohydrate intake for maximum weight loss.

Setting Up Your Carb Intake

Our point of reference here is going to be a study conducted in 2005 by Cornier et. al. – PubMed ID 15897479. The objective of this study was to find out how different macronutrient compositions in an energy-restricted diet (subjects eating below maintenance) could enhance the effectiveness of weight loss for individuals of varying insulin tolerance levels.

For this purpose, two types of diets were prepared: a high-carb (HC) diet, with a macronutrient split (Protein / Carbs / Fats) of 20%/60%/20%, and a low-carb (LC) diet, with a 20%/40%/40% split. As you can see, protein intake was the same in both diets – it is just the ratio of carbs to fats that was being manipulated.

Next: 21 obese, non-diabetic women were divided into four groups, as follows:

  • Insulin-resistant group on a HC diet.
  • Insulin-resistant group on a LC diet.
  • Insulin-sensitive group on a HC diet.
  • Insulin-sensitive group on a LC diet.

The whole trial lasted a total of 16 weeks, and the results were as follows:

  • The insulin-resistant group on the HC diet lost ~8.5% of total initial body weight (TIBW).
  • The insulin-resistant group on the LC diet lost ~13.4% of TIBW.
  • The insulin-sensitive group on the HC diet lost ~13.5% of TIBW.
  • The Insulin-sensitive group on the LC diet lost ~6.8% of TIBW.

What Does This Mean?

Only what the researchers concluded: that insulin-resistant obese women lost almost 60% more on a low-carb diet, while insulin-sensitive obese women lost almost 100% more on a high-carb diet.

Unfortunately the researchers weren’t clear on body fat changes, as they seem to have only monitored the subjects’ body weight. I would have loved to see BF figures in this one, as when carbs are concerned, water retention is always a big factor. However, to their credit, the trial lasted 4 whole months, which makes their results quite reliable.

As per my current level of knowledge, the mechanism behind this entire process is not clear yet. However, this shouldn’t stop us from making the best of it.

How Can You Use This Knowledge?

I’m pretty sure you’ve already figured this one out: you will simply need to base your carbohydrate intake on your level of insulin tolerance. Here are my recommendations (this assumes that you are on a calorie deficit, attempting to lose weight), and contrary to what the researchers did in their trial, which was calculating macros as a percentage of total daily calorie intake, I’m going to use a bit of a different approach:

Protein requirements will not change regardless, and should be limited to between 1 and 1.5 grams per pound of your lean body mass. Please note, however, that I suggest sticking to the lower end of that range, unless you have reason to believe that you need more protein. For most people, 1g will be enough in my experience.

Now you need to calculate your fat intake, which will be based on your insulin sensitivity:

If you are insulin-resistant, consume 0.65 grams of fat per pound of lean body mass.

If you are insulin-sensitive, consume 0.45 grams of fat per pound.

Once you do that, you’ll be left with a few calories towards your daily energy requirement – you fill those up with carbohydrates. To make sure that this is understood, I will give you an example.

Let’s assume you’re a male, with a 160 pound LBM, looking to lose weight, and are insulin-resistant. You calculate your daily energy expenditure to be 2,500 calories, so in order to lose weight, you create a 600 calorie restriction, meaning you’d end up consuming 1,900 calories per day.

First you calculate your protein. This one is easy: 1 x 160 (your LBM) = 160 grams of protein. 160 x 4 (calories per gram of protein) equals 640 calories that you’ll be getting from protein.

Now calculate your fats. 0.65 x 160 = 104 grams of fat. 104 x 9 (calories per gram of fat) = 936 calories that you’ll be getting from dietary fats.

Adding the energy contents of proteins and fats, we get 640 + 936 = 1576 calories in total. Since your daily calorie goal is 1,900, this means that you have 324 calories left. Those go towards your carbohydrates. And we know that there are 4 calories per gram of carbs, so the final figure would be 324 / 4 = 81 grams that you should consume from carbs.

So you would be consuming 160 grams of protein, 104 grams of fat, and 81 grams of carbohydrates in this example.

Wrapping It All Up

Your mileage may vary, of course. And it is quite likely that you will need to adjust your carbohydrate/fat intake and play around a bit to find a balance that is right for YOU. Make sure to keep track of everything though so you can draw some meaningful conclusions later on, otherwise you could end up wasting 8 weeks and have no clue what was working best for you.

Hopefully the above will help you get even more out of your weight loss attempt. Good luck!


About the Author – Mark Nazzal has a passion for helping others achieve weight loss. His site, helps provide weight loss information for everyone.

3 thoughts on “Setting Carb Intake Based on Insulin Tolerance”

  1. I hope so 🙂 It’s all really easier than may seem at first glance; 6-8 weeks of trial and error and you’ll know everything you need, and can later use that information for many years to come.

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