Do Ultra-Processed Foods Make You Fat?

Written by Dr. Steve Chaney on . Posted in ultra-processed foods

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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Latest Article

Can Plant-based Diets Be Unhealthy?

Posted September 10, 2019 by Dr. Steve Chaney

Do Plant-Based Diets Reduce Heart Disease Deaths?

Author: Dr. Stephen Chaney

 

plant-based diets vegetablesPlant-based diets have become the “Golden Boys” of the diet world. They are the diets most often recommended by knowledgeable health and nutrition professionals. I’m not talking about all the “Dr. Strangeloves” who pitch weird diets in books and the internet. I am talking legitimate experts who have spent their life studying the impact of nutrition on our health.

Certainly, there is an overwhelming body of evidence supporting the claim that plant-based diets are healthy. Going on a plant-based diet can help you lower blood pressure, inflammation, cholesterol and triglycerides. People who consume a plant-based diet for a lifetime weigh less and have decreased risk of heart disease, diabetes, and cancer.

But, can a plant-based diet be unhealthy? Some people consider a plant-based diet to simply be the absence of meat and other animal foods. Is just replacing animal foods with plant-based foods enough to make a diet healthy?

Maybe not. After all, sugar and white flour are plant-based food ingredients. Fake meats of all kinds abound in our grocery stores. Some are very wholesome, but others are little more than vegetarian junk food. If you replace animal foods with plant-based sweets, desserts, and junk food, is your diet really healthier?

While the answer to that question seems obvious, very few studies have asked that question. Most studies on the benefits of plant-based diets have compared population groups that eat a strictly plant-based diet (Seventh-Day Adventists, vegans, or vegetarians) with the general public. They have not looked at variations in plant food consumption within the general public. Nor have they compared people who consume healthy and unhealthy plant foods.

This study (H Kim et al, Journal of the American Heart Association, 8:e012865, 2019) was designed to fill that void.

 

How Was The Study Done?

plant-based diets studyThis study used data collected from 12,168 middle aged adults in the ARIC (Atherosclerosis Risk in Communities) study between 1987 and 2016.

The participant’s usual intake of foods and beverages was assessed by trained interviewers using a food frequency questionnaire at the time of entry into the study and again 6 years later.

Participants were asked to indicate the frequency with which they consumed 66 foods and beverages of a defined serving size in the previous year. Visual guides were provided to help participants estimate portion sizes.

The participant’s adherence to a plant-based diet was assessed using four different well-established plant-based diet scores. For the sake of simplicity, I will include 3 of them in this review.

  • The PDI (Plant-Based Diet Index) categorizes foods as either plant foods or animal foods. A high PDI score means that the participant’s diet contains more plant foods than animal foods. A low PDI score means the participant’s diet contains more animal foods than plant foods.
  • The hPDI (healthy plant-based diet index) is based on the PDI but emphasizes “healthy” plant foods. A high hPDI score means that the participant’s diet is high in healthy plant foods (whole grains, fruits, vegetables, nuts, legumes, coffee and tea) and low in animal foods.
  • The uPDI (unhealthy plant-based diet index) is based on the PDI but emphasizes “unhealthy” plant foods. A high uPDI score means that the participant’s diet is high in unhealthy plant foods (refined grains, fruit juices, French fries and chips, sugar sweetened and artificially sweetened beverages, sweets and desserts) and low in animal foods.

For statistical analysis the scores from the various plant-based diet indices were divided into 5 equal groups. In each case, the group with the highest score consumed the most plant foods and least animal foods. The group with the lowest score consumed the least plant foods and the most animal foods.

The health outcomes measured in this study were heart disease events, heart disease deaths, and all-cause deaths. Again, for the sake of simplicity, I will only include 2 of these outcomes (heart disease deaths and all-cause deaths) in this review. The data on deaths were obtained from state death records and the National Death Index. (Yes, your personal information is available on the web even after you die.)

 

Do Plant-Based Diets Reduce Heart Disease Deaths?

plant-based diets reduce heart deathsThe participants in this study were followed for an average of 25 years.

The investigators looked at heart disease deaths over the 25 years and compared people with the highest intake of plant foods to people with the highest intake of red meat and other animal foods. The results were:

  • People with the highest intake of plant foods and the highest intake of healthy plant foods (whole grains, fruits, vegetables, nuts, legumes, coffee and tea) had a 19-32% lower risk of dying from heart disease than people with the highest intake of red meat and other animal foods.
  • People with the highest intake of unhealthy plant foods (refined grains, fruit juices, French fries and chips, sugar sweetened and artificially sweetened beverages, sweets and desserts) had the same risk of dying from heart disease as people with the highest intake of red meat and other animal foods.

When the investigators looked at all-cause deaths over the 25 years:

  • People with the highest intake of plant foods and the highest intake of healthy plant foods had an 11-25% lower risk of dying from any cause than people with the highest intake of red meat and other animal foods.
  • People with the highest intake of unhealthy plant foods had the same risk of dying from heart disease as people with the highest intake of red meat and other animal foods.

What Else Did The Study Show?

The investigators made a couple of other interesting observations:

  • The association of the overall diet with heart disease and all-cause deaths was stronger than the association of individual food components. This underscores the importance of looking at the effect of the whole diet on health outcomes rather than the “magic” foods you hear about on Dr. Strangelove’s Health Blog.
  • Diets with the highest amount of healthy plant foods were associated with higher intake of carbohydrates, plant protein, fiber, and micronutrients, including potassium, magnesium, iron, vitamin A, vitamin C, folate, and lower intake of saturated fat and cholesterol.
  • Diets with the highest amount of unhealthy plant foods were associated with higher intake of calories and carbohydrates and lower intake of fiber and micronutrients.

The last two observations may help explain some of the health benefits of plant-based diets.

 

Can Plant-Based Diets Be Unhealthy?

plant-based diets unhealthy cookiesNow, let’s return to the question I asked at the beginning of this article: “Can plant-based diets be unhealthy?” Although some previous studies have suggested that unhealthy plant-based diets might increase the risk of heart disease, this study did not show that.

What this study did show was that an unhealthy plant-based diet was no better for you than a diet containing lots of red meat and other animal foods.

If this were the only conclusion from this study, it might be considered a neutral result. However, this result clearly contrasts with the data from this study and many others showing that both plant-based diets in general and healthy plant-based diets reduce the risk of heart disease deaths and all-cause deaths compared to animal-based diets.

The main message from this study is clear.

  • Replacing red meat and other animal foods with plant foods can be a healthier choice, but only if they are whole, minimally processed plant foods like whole grains, fruits, vegetables, nuts, legumes, coffee and tea.
  • If the plant foods are refined grains, fruit juices, French fries and chips, sugar sweetened and artificially sweetened beverages, sweets and desserts, all bets are off. You may be just as unhealthy as if you kept eating a diet high in red meat and other animal foods.

There is one other subtle message from this study. This study did not compare vegans with the general public. Everyone in the study was the general public. Nobody in the study was consuming a 100% plant-based diet.

For example:

  • The group with the highest intake of plant foods consumed 9 servings per day of plant foods and 3.6 servings per day of animal foods.
  • The group with the lowest intake of plant foods consumed 5.4 servings per day of plant foods and 5.6 servings per day of animal foods.

In other words, you don’t need to be a vegan purist to experience health benefits from adding more whole, minimally processed plant foods to your diet.

 

The Bottom Line

A recent study analyzed the effect of consuming plant foods on heart disease deaths and all-cause deaths over a 25-year period.

When the investigators looked at heart disease deaths over the 25 years:

  • People with the highest intake of plant foods and the highest intake of healthy plant foods had a 19-32% lower risk of dying from heart disease than people with the highest intake of red meat and other animal foods.
  • People with the highest intake of unhealthy plant foods had the same risk of dying from heart disease as people with the highest intake of red meat and other animal foods.

When the investigators looked at all-cause deaths over the 25 years:

  • People with the highest intake of plant foods and the highest intake of healthy plant foods had an 11-25% lower risk of dying from any cause than people with the highest intake of red meat and other animal foods.
  • People with the highest intake of unhealthy plant foods had the same risk of dying from heart disease as people with the highest intake of red meat and other animal foods.

The main message from this study is clear.

  • Replacing red meat and other animal foods with plant foods can be a healthier choice, but only if they are whole, minimally processed plant foods like whole grains, fruits, vegetables, nuts, legumes, coffee and tea.
  • If the plant foods are refined grains, fruit juices, French fries and chips, sugar sweetened and artificially sweetened beverages, sweets and desserts, all bets are off. You may be just as unhealthy as if you kept eating a diet high in red meat and other animal foods.

A more subtle message from the study is that you don’t need to be a vegan purist to experience health benefits from adding more whole, minimally processed plant foods to your diet. The people in this study were not following some special diet. The only difference was that some of the people in this study ate more plant foods and others more animal foods.

For more details on the study, 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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