Wednesday, September 13, 2023

Glycemic Index And Brain Function

The Study

In this interesting study, 25 type 2 diabetics consumed a high or low glycemic breakfast, lunch and dinner on 2 separate occasions. The glycemic index is a measure of how a carbohydrate food impacts your blood sugar. High glycemic foods cause a spike in glucose and insulin levels and low glycemic foods have a more modest impact on blood sugar and insulin. All subjects went through a battery of cognitive tests during each study day.

The subjects had a significant improvement in global cognitive and executive functioning when comparing the low glycemic day to the high glycemic day.

American Journal of Clinical Nutrition 2023; 117:859-69.
Take Home Message

It sounds funny saying this, but the way you eat can impact how smart you are. Your brain works better when you eat in a way that provides a stable blood sugar.

The authors proposed several potential mechanisms for the cognitive benefits seen in this study after the low-glycemic index meal plan:

-More energy on the low GI day was responsible for the improvements in cognitive function.

-A better mood on the low GI day was responsible for the improvements in cognitive function.

-Less hunger on the low GI day was responsible for the improvements in cognitive function.

-Improvements in cerebral blood flow may also be responsible.

When it comes to carbs, focus on fruits, vegetables, legumes and whole grains such as oatmeal, quinoa and brown rice. Strictly limit bread, pasta, white rice and sugar.

Gut Microbiome And Body Weight

The Study

Recent research has shown that our gut microbiome may influence energy balance. In this interesting crossover trial, 31 young and normal weight men and women consumed a Western Diet and a Microbiome Enhancing Diet for 23 days each. 

Both of these diets had the same number of calories and macronutrient break down. The Western Diet was a typical unhealthy American way of eating. The Microbiome Enhancer Diet was high in fiber, resistant starch, had a larger particle size and fewer processed foods.

After each dietary intervention, a variety of measurements were taken.

During the Microbiome Enhancing Diet protocol, subjects lost 116 calories per day in their feces.

Nature Communications 2023; 14:3161.

Take Home Message

This is a truly fascinating study. 116 calories may not sound like much, but in a year, it adds up to 12 lbs. lost. The gut microbiome is emerging as something of a control center for energy balance. How it does this is unclear, but there are a few theories:
1) It has an influence on the number of calories harvested from food.
2) It has an influence on gut hormones.
3) Signaling through microbiome metabolic byproducts such as SCFA’s (short chain fatty acids).

There are many reasons to eat a diet high in fiber and low in processed foods. You can potentially add enhancing your gut microbiome to the list.

Product Review: Cooper Complete Basic One Iron Free Multivitamin

Many of my clients ask me if I take a multivitamin and if I have one to recommend. The answer is yes to both questions. But before we get to that, just a bit of background. If you have worked with me or read any of my books, you likely know that I am not a supplement guy. There are several reasons why this is true:

-It is always better to get whatever nutrients you are looking for by eating healthy.

-Because of the 1994 Dietary Supplement Health And Education Act, there is virtually no regulation of the supplement industry. In other words, no one is testing if your supplement has what it says it does. And no one is testing whether anything else unsafe may be added to it. This has caused a ton of problems. Some supplements have been found to have prescription drugs like Prozac or Viagra when tested. Not good!

However, multivitamins have several benefits:

-Recently a Harvard study showed that taking a daily multivitamin improved memory and slowed cognitive decline in older adults (Reference 1).

-Most of us need to supplement vitamin D, particularly in the winter months. It is really hard to get enough from your food. You can find a multivitamin that includes Vitamin D to take care of this.

-A multivitamin can act as insurance for your healthy diet. Sometimes even the best diets lack certain nutrients. A multivitamin can make up this small difference.

I have for years been recommending a great multivitamin sold by Cooper Concepts. It is called Cooper Complete Basic One Iron Free. Dr. Kenneth Cooper is an amazing Physician, Researcher and Entrepreneur who has focused on exercise and preventative health for his entire career. One of his companies, Cooper Concepts, sells a one a day multivitamin that checks all my boxes.


1) Dr. Cooper consulted with leading nutrition researchers, including the Department of Nutrition at Harvard School of Public Health, to help him determine what nutrients to include in this multivitamin. 

2) This vitamin contains 2000 IU’s of Vitamin D.

3)Most importantly, Dr. Cooper has an independent lab test this multivitamin to be sure that it contains what it says it does and nothing else. This is huge!


1) This multivitamin is a bit more expensive than other brands. It is priced at $29.98 for 60 tablets.

What I Recommend To My Clients

If a client’s diet is otherwise good, I recommend taking this multivitamin 3 times per week as insurance and to make sure they are getting enough vitamin D. This is particularly important in the winter, when the sun is less strong (we make vitamin D through our skin from sun exposure).

This also brings the cost down quite a bit. At 12 pills a month, the bottle will last 5 months or so, which is $6 a month. Since each pill contains 2000 IU of Vitamin D, taking 3 a week averages just over 800 IU per day, which is a level I am comfortable with. For more information or to pick up this multivitamin, click here.


1) American Journal Of Clinical Nutrition 2023 118:273-82

Disclosure: I am not affiliated with the company that makes Cooper Complete supplements and make no money if you buy any of their products.