Which Foods Lower Blood Sugar?

Written by Dr. Steve Chaney on . Posted in Blood Sugar

Can You Believe The “Experts”?

Author: Dr. Stephen Chaney

which foods lower blood sugarYour blood sugar levels have been creeping up. Your doctor has been bugging you to do something about it – even threatening to put you on medications if you don’t get your blood sugar under control. So, which foods lower blood sugar?

Now it’s the first of the year, and you’ve vowed to do something about it. You have vowed to make better food choices. That should be easy. There is lots of great advice about foods that lower blood sugar on the internet. For example, in a recent search, I found articles proclaiming “9 foods that lower blood sugar”, “7 foods that control blood sugar”, and “12 power foods to beat diabetes”.

But, are those foods the right ones for you? What if we are remarkably different in our blood sugar responses to the same food? This is just what a recent study suggests.

How Was The Study Designed?

A group of scientists in Isreal set out to test the hypothesis that people eating identical meals might have a high variability in their post-meal blood glucose response (Zeevi et al, Cell, 163, 1079-1094, 2015).

measure glucoseThe investigators enrolled 800 subjects ages 18-70 into their study. None of the individuals had diabetes. However, 54% of them were overweight (BMI ≥ 25 kg/m2) and 22% of them were obese (BMI ≥ 30 kg/m2). Thus, their subject population was typical of the adult population of almost every Western, industrialized country.

All 800 subjects were followed for one week during which time:

  • They were connected to a continuous glucose monitor, which measured their blood glucose levels every 5 seconds.
  • They were given a Smartphone app and instructed to log their food intake, exercise, and sleep in real time.
  • They were told to follow their normal daily routine and dietary habits except for the first meal of every day, which consisted of five different types of standardized “meals” (glucose, fructose, bread, bread with butter, bread with chocolate), all providing 50 gm of available carbohydrate.

The glucose monitor recorded blood sugar responses for 2 hours following each meal. From that information, the investigators calculated a PPGR (post-prandial glycemic response), which I will mercifully refer to as “blood sugar response”, for every meal eaten by every subject throughout the week.

The standardized “meals” eaten at the beginning of the day were used to validate the study. For example:

  • Two of the standardized meals were given to each subject twice during the study separated by at least one day.
    • There was very little variability in blood sugar response when the same standardized meal was given to the same subject on different days.
    • However, there was a significant amount of variability in blood sugar response when the same standardized meal was given to different subjects.
  • The average blood sugar response to each of the standardized meals was very similar to literature values from previous studies (Most previous studies have reported only average blood sugar responses, not individual variability).

In short, the results from the standardized “meals” validated both the reliability and reproducibility of the data.

Finally, to eliminate as many confounding variables as possible, the investigators compared blood sugar response only for those meals in which a single food was the major component of the meal and that food provided 20-40 gm of carbohydrate.

Here is where things got really interesting!

Which Foods Lower Blood Sugar?

breadThis study showed that there is tremendous individual variability in the blood sugar response to any given food. For example, individual blood sugar responses varied by:

  • 4-fold for sugar-sweetened soft drinks, grapes and apples.
  • 5-fold for rice.
  • 6-fold for bread and potatoes.
  • 7-fold for ice cream and dates.

Put another way:

  • Some people had almost no blood sugar response to cookies, but a very high blood sugar response to a banana.
  • Other people had almost no blood sugar response to bananas, but a very high blood sugar response to cookies.

That is a pretty striking result. Which foods lower blood sugar? This study suggests that some people trying to control their blood sugar can eat bananas, while others should avoid them. It might even mean that some people trying to control blood sugar can eat cookies. I know that is what many people would like to hear, but I’m not ready to make that recommendation.

Why Is There So Much Individuality in Blood Sugar Response?

good food choicesYou are probably wondering why there is such variability in blood sugar response to the same foods. There are several factors that influence individual blood sugar response. For example,

  • Overweight and obesity (Both tend to increase blood sugar response).
  • Dietary habits (Meats, particularly fatty meats, processed grains, and simple sugars tend to increase blood sugar response to a given amount of carbohydrate. Unprocessed grains, fresh fruits & vegetables tend to decrease blood sugar response to a given amount of carbohydrate).
  • What we eat with a given meal (Protein, fiber, and fat in a meal can decrease blood sugar response to the carbohydrate in that meal).
  • Physical activity (Increased muscle mass decreases blood sugar response to a given amount of carbohydrate).
  • The bacteria in our intestine (This may be a chicken-and egg thing. The bacteria in our intestine are influenced by our dietary habits.)
  • Genetics.
  • Things we don’t yet know about.

The good news is that we can actually control some of these variables. The ones over which we have the most control are weight, dietary habits, what we eat along with the carbohydrates in our meals, and physical activity.

What Does This Mean For You?

blood sugarThe authors concluded that “universal dietary recommendations [for lowering blood sugar levels] may have limited utility.”  That is because dietary recommendations are based on average responses and none of us are average. As the saying goes “We are all wonderfully [and differently] made”.

So, when you read about diets and foods that will help you keep your blood sugar levels under control, take those recommendations with a grain of…sugar. They are a good starting place, but you need to listen to your body, and eat the foods that work best for you.  So, which foods lower blood sugar?  It is different for different people, but there are some variables you can control.

Don’t get carried away, however. I’m pretty sure Twinkies washed down with a soft drink are bad for just about everyone.

More importantly, control the variables you can – weight, dietary habits, foods you eat along with carbohydrates, and physical activity. If you control those four variables, you will be well on your way to ideal blood sugar control.

 

The Bottom Line

 

  • A recent study has shown that there is tremendous variability in blood sugar response to identical meals from one individual to the next.
  • The authors of the study concluded that “universal dietary recommendations [for lowering blood sugar levels] may have limited utility.” That is because dietary recommendations are based on average responses, and none of us are average.
  • So, when you read about diets and foods that will help you keep your blood sugar levels under control, take those recommendations with a grain of…sugar. They are a good starting place, but you need to listen to your body, and eat the foods that work best for you.
  • There are variables influencing our blood sugar response that we cannot control, such as genetics. However, there are some very important variables that we can control. For example, we can improve our blood sugar response by:
    • Attaining and maintaining ideal weight. Losing as little as 5-10 pounds can result in a significant improvement.

 

    • Eating a diet that emphasizes fresh fruits & vegetables, nuts, and whole grains and minimizes meats, especially fatty meats, processed grains, and simple sugars. This may act by influencing the bacteria that populate our intestine.

 

    • Consuming carbohydrates along with protein, fiber-rich foods, and even some fat in the same meal.

 

    • Increasing physical activity, especially activity that increases lean muscle mass.

 

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

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Latest Article

Do Ultra-Processed Foods Make You Fat?

Posted June 25, 2019 by Dr. Steve Chaney

What Is The Secret For Weight Loss?

Author: Dr. Stephen Chaney

 

Do ultra-processed foods make it harder to loose weight?

ultra-processed foods questionsIt is so confusing. It seems like everyone has a magical weight loss diet. You just follow their diet and the pounds will melt away. The problem is that everyone’s recommendations are different. What is the average consumer to think? Is the best diet low fat, low carb, low sugar, Paleo, Keto, or vegan? Or is intermittent fasting the secret to successful weight loss?

What if the secret to weight loss was none of the diets mentioned above, yet was something common to all of them?

The one common feature of every popular diet is they cut out sodas and processed foods and replace them with whole unprocessed foods. What if cutting out highly processed foods was the secret to successful weight loss, and none of the other restrictions of the various diets really mattered?

There are lots of studies suggesting that ultra-processed foods might be the problem. [Note: In the scientific community the term highly processed foods has been replaced with ultra-processed foods. There are subtle differences between the two terms, but for our purposes we will consider them identical]. Consumption of ultra-processed foods has been shown to be associated with overeating, obesity, poor health outcomes, and premature death.

For example, consumption of ultra-processed foods and obesity have increased in parallel. Today ultra-processed foods constitute the majority of calories consumed in America, and 40% of Americans are now obese.

However, associations don’t prove cause and effect. In the words of the authors of the latest study: “There has never been a randomized controlled trial demonstrating any beneficial effects of reducing ultra-processed foods or deleterious effects of increasing ultra-processed foods in the diet.”

The latest study (KD Hall et al, Cell Metabolism, 30: 1-11, 2019 ) was the first randomized controlled trial designed to test the hypothesis that consumption of ultra-processed foods leads to obesity.

 

How Was The Study Done?

ultra-processed foods studyTwenty overweight subjects (10 men and 10 women) volunteered for the study. Their average age was 31 and their average BMI was 27, which means they were overweight, but not obese. All were weight-stable in the months preceding the study.

They were admitted to the metabolic ward at the NIH where every aspect of what they ate and the exercise they got was controlled. The subjects were randomly assigned to consume an ultra-processed or an unprocessed diet for two weeks followed by the alternative diet for the final two weeks.

During the study the subjects were given three meals a day that provided twice the calories they were accustomed to eating plus unlimited snacks. They were instructed to eat as much or as little as they desired. The calories consumed were calculated based on how much food they left on their plates.

The ultra-processed diet and unprocessed diets were matched with respect to:

  • Total calories in the food portions given to the subjects.
  • Caloric density (calories per serving size).
  • Macronutrients (carbohydrate, fat, & protein).
  • Sugars, fiber, and sodium.

The ultra-processed and unprocessed diets were neither low fat, low carb, or high protein. The caloric composition was around 48% carbohydrate, 35% fat, and 17% protein.

However, because of the differences between ultra-processed and unprocessed foods, it was impossible to match all parameters. For example, the ultra-processed and unprocessed diets differed significantly in:

  • Added sugar: 54% of the sugar in the ultra-processed diet was added sugar versus only 1% added sugar in the unprocessed diet.
  • Insoluble fiber: 16% of the fiber in the ultra-processed diet was insoluble fiber versus 77% in the unprocessed diet.
  • Saturated fat: 34% of the fat in the ultra-processed diet was saturated versus 19% in the unprocessed diet.
  • Omega-6 to omega-3 ratio: The ratio was 11:1 in the ultra-processed diet versus 5:1 in the unprocessed diet.

To give you an example of what the two diets looked like, dinner one night for the unprocessed diet group consisted of beef tender roast with barley and spinach and a parfait made of fresh berries and nonfat, unflavored Greek yogurt while the ultra-processed diet group got processed turkey and cheese sandwiches (on white bread) with baked chips, canned peaches and nonfat vanilla Greek yogurt. For breakfast one morning the unprocessed diet group got omelets made from fresh eggs while the ultra-processed diet group got omelets made from Fresh Start liquid.

 

Do Ultra-Processed Foods Make You Fat?

ultra-processed foods make you fatThe results of the study were quite interesting:

  • Subjects ate an additional 508 calories per day when on the ultra-processed diet.
  • Those extra calories came from both carbohydrate and fat, not from protein.
  • Subjects gained 2 pounds in just two weeks on the ultra-processed diet and lost 2 pounds in two weeks on the unprocessed diet.
  • Subjects ate their food more quickly on the ultra-processed diet (50 calories/minute) than on the unprocessed diet (32 calories/minute).

The authors of the study asked the participants several subjective questions about the two diets to better understand why they consumed more calories on the ultra-processed diet. However, those questions did not provide any useful insights. For example, the subjects rated the two diets equally with respect to:

  • Palatability and familiarity of the foods in the diet.
  • Hunger prior to eating and both fullness and satisfaction when they were finished eating.

These findings surprised the authors. The authors had assumed their subjects would eat more ultra-processed foods because they liked them better.

With respect to the overall study results, the authors concluded: “Limiting consumption of ultra-processed foods may be an effective strategy for obesity prevention and treatment.”

In short, their study confirms what many experts have long suspected, but does not provide a mechanistic explanation of why ultra-processed foods lead to overconsumption and obesity.

 

What Is The Secret For Weight Loss?

 

ultra-processed foods secretThe arguments over which diet is best for weight loss never end. Everyone claims they have the secret, and everyone quotes studies showing their diet works.

Yet the diets are as different as night and day. They shouldn’t all work, but they do. For example, weight loss is virtually identical on a very low-fat vegan diet and a very low carb keto diet. That tells us that the secret can’t be either low-fat or low carb.

The secret must be something all these diets have in common. When you ask what they have in common, the answer is simple. All the popular diets start by eliminating sodas and ultra-processed foods and replacing them with unprocessed foods.

Could it be that something as simple as eliminating sodas and ultra-processed foods and replacing them with unprocessed foods is the secret to successful weight loss? Many experts have hypothesized that ultra-processed foods were the cause of the obesity epidemic, but this is the first randomized controlled clinical trial to prove that hypothesis.

Like any individual study, this study needs to be confirmed by additional randomized controlled studies. One might hope for longer duration studies with more subjects, but it would be very difficult to duplicate the precision of this study. Asking volunteers to enter a metabolic ward where every aspect of their life is controlled for multiple weeks is both expensive and a huge commitment by the volunteers.

My recommendation is simple. You don’t have to choose radical diets that eliminate whole food groups to lose weight successfully. They are hard to follow and may not be healthy long-term. Just ditch the sodas, junk foods, and highly processed foods. Rediscover the pleasures of whole unprocessed foods. You will lose weight gradually and safely. You will be healthier.

Of course, it is not quite that simple.

  • Portion control is essential. You can eat too much unprocessed food.
  • Caloric density (calories per serving) is important. This is one reason why primarily plant-based diets are generally more successful for long-term weight control.
  • Practice mindful eating. Savor your food and eat it slowly. You will be less likely to overeat.
  • And, of course, don’t neglect the exercise component.

For a more detailed analysis of the pros and cons of popular diets, read my book, “Slaying The Food Myths.”

 

The Bottom Line

 

It seems like everyone has a magical weight loss diet. You just follow their diet and the pounds will melt away. The problem is that everyone’s recommendations are different. What is the average consumer to think? Is the best diet low fat, low carb, low sugar, Paleo, Keto, or vegan? Or is intermittent fasting the secret to successful weight loss?

What if the secret to weight loss was none of the diets mentioned above, yet was something common to all of them? The one common feature of every popular diet is they cut out sodas and processed foods and replace them with whole unprocessed foods.

For years experts have claimed that the consumption of highly processed foods is responsible for the obesity epidemic and replacing  ultra-processed foods with unprocessed foods was the secret to successful weight loss. However, those claims are based on associations, and association studies do not prove cause and effect.

Finally, the first randomized controlled trial to test this hypothesis has been published. The study showed:

  • Subjects ate an additional 508 calories per day when on the ultra-processed diet.
  • Subjects gained 2 pounds in just two weeks on the ultra-processed diet and lost 2 pounds in two weeks on the unprocessed diet.

My recommendation is simple. Just ditch the sodas, junk foods, and highly processed foods. Rediscover the pleasures of whole unprocessed foods. You will lose weight gradually and safely. You will be healthier.

Of course, it’s not quite that simple. I discuss other aspects of successful weight loss in the article above.

For a more detailed analysis of the pros and cons of popular diets, read my book, “Slaying The Food Myths.”

For more details read the article above.

 

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

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