“The US Dietary Guidelines- Why They Matter and How They Might Change”
A summary of Nina Teicholz’s presentation at Low Carb Denver
Introduction
Nina Teicholz is a Journalist from California who is best known for her NY Times best selling book “The Big Fat Surprise.” In her presentation at Low Carb Denver, Nina questioned the quality of scientific data used to develop The USDA Dietary Guidelines. In this article, I will summarize Nina’s presentation and add my own thoughts at the end.
What are The Dietary Guidelines?
The Dietary Guidelines are dietary recommendations created every 5 years by the USDA for Americans over the age of 2 years old. These guidelines were created to help health professionals and policymakers advice Americans about healthy choices in their diet. They are also the basis of the Food Pyramid and MyPlate guidelines.
The guidelines recommend eating more fruits and vegetables, more whole grains, lean meats, low-fat dairy and to avoid saturated fat.
Have the guidelines helped us?
Since the initiation of The Dietary Guidelines in 1980, there has been a dramatic increase in obesity. Nina acknowledged that this relationship between obesity and the initiation of The Dietary Guidelines is a correlation and not a causation. However it is interesting to note that these guidelines certainly have not helped our country fight obesity.
Why should we care about the dietary guidelines?
The Dietary Guidelines have a huge influence on America’s food choices. This is because they influence many American educational and feeding programs. Here you can see the many programs that these guidelines influence including USDA Feeding Programs, The Department of Education, Health Professional Associations, The military and The US Food Supply.
WIC
WIC (Women, Infants and Children) is a USDA supplemental feeding program that provides food to low-income mothers in the US. The food provided by WIC is based off of The Dietary Guidelines. Fruit juice, cereal, low-fat milk, beans, and nut butters are provided to the low-income mothers who participate in the program.
School Lunch Program
Here is a picture of a typical meal provided by The School Lunch Program, another USDA Feeding Program that is based off The Dietary Guidelines.
American Medical Association
The Dietary Guidelines are the basis of nutrition education taught in medical school. Out of the 8 years of med school education, only 1-2 days are dedicated to teaching students about nutrition. If you are a medical professional working for a large practice, you are not allowed to recommend a diet outside of The Dietary Guidelines.
The Military
The rations distributed in the military are based off The Dietary Guidelines. There is a problem of obesity in the US military with 7% of military now obese. In her lecture, Nina noted a study that demonstrated that US Military gain weight after enrolling in the military. She highlighted this is unusual when you consider how active military personal are. Here is an example of a meal plan provided to military personal that is based off the guidelines. Foods highlighted in yellow are considered ok, green are good and red are bad in accordance to the guidelines.
As you can see, egg whites are recommended over whole eggs and animal proteins like ham and shredded cheese are not recommended.
US food supply
The Dietary Guidelines also directly influences the food that is available on our shelves. After their implementation, The USDA sent out notices to food companies to produce low-fat food options like low-fat granola bars and cereals. These dietary recommendations influence every one of us.
Maybe we do not follow the guidelines?
A common argument is that we just do not follow The Dietary Guidelines. Americans just eat poorly and exercise too little. Nina presented this graph on food availability, showing that we have been following the guidelines. The blue lines are foods that we have been recommended to eat while the red lines are foods we have been recommended to avoid.
According to food availability data from 1970-2014, we have increased our vegetable consumption by 20%, fresh fruits by 35%, grains by 28%, vegetable oils up by 87%. We have decreased our consumption of red meat by 28%, eggs down by 13%, animal fat down by 27% and butter down by 9%. The loss-adjusted food availability data also shows an overall decrease in animal foods by 8%, an increase in plant foods minus sugar by 44%.
On exercise
According to the latest CDC (Center of Disease Control) report, Americans are exercising more. We have had an increase in physical activity since 2005. 54% of Americans in 2016 meet the government’s physical activity guidelines vs 41% in 2005.
On calories
According to CDC, we do consume about 200-300 more calories than we did in 1980. However, 98% of these calories comes from carbohydrates. I have attached a graph that demonstrates this data from Nina’s non-profit The Nutrition Coalition:
How The Dietary Guidelines are out of step with science
During the remainder of Nina’s presentation, she summarized her paper “How The Dietary Guidelines are Out of Step with Science” that was published in The British Medical Journal back in 2015. She noted that this paper received a lot of criticism from many scientists and researchers who wanted to get her paper retracted. Nina said that the paper survived with some exacted corrections. None of these exacted corrections affected the key allegations of the paper. She explained that the information she used for her presentation at Low Carb Denver was never challenged and that her paper has been formally peer-reviewed twice.
The Dietary Pattern Recommendations
The Dietary Guidelines recommends 3 dietary patterns: The DASH diet, The Mediterranean Diet and The Vegetarian Diet. Nina summarized the nutrition studies used to validate these dietary recommendations:
The Mediterranean Diet:
PREDIMED Study is the main study used by The Dietary Guidelines to recommend The Mediterranean Diet. This study was recently retracted and then republished after major protocol deviations were noted. Even if you can accept the flawed study structure, the study only showed a 0.2% difference in cardiovascular risk and death between the control diet and the mediterranean diet.
US-DASH
Here are the 8 trails The Dietary Guidelines used to recommend the DASH-Diet. As you can see, all of these trials are under a year in length:
Vegetarian Diet
This is the first year The Advisory Committee added a Vegetarian Diet as one of their recommended dietary eating patterns. Nina noted that The Committee was clearly looking for data to justify this diet. 11 out of the 14 advisory members expressed a bias for a vegetarian/vegan diet. This committee could find no randomized controlled trials to support the vegetarian diet.
How do these diets impact disease outcomes?
Question 1: what is the relationship between diet and cardiovascular disease risk?
The Dietary Guidelines used the PREDIMED Trials and DASH trials as evidence that their recommended diets reduce cardiovascular disease risk. As Nina noted earlier, The PREDIMED trial was seriously flawed and only showed a 0.02% difference in cardiovascular risk between the control diet and the mediterranean diet.
Question 2: What is the relationship between dietary patterns and measures of body weight or obesity?
One 2-year trial on 180 subjects with metabolic syndrome patients on a Mediterranean diet lost 6lbs vs. low-fat controls.
Question 3: What is the relationship between dietary patterns and the rise of diabetes?
The Dietary Guidelines presented zero clinical trials to show that any of their recommended dietary patterns can prevent or reverse type 2 diabetes.
USDA Dietary Patterns compared to Low Carb Diets
After reviewing the clinical trials used to support the 3 recommended USDA Dietary Patterns, Nina then compared this information to The Low-Carb Diet clinical trial evidence that was available to committee members at the time The Dietary Guidelines were being developed.
As you can see, during the development of the most recent Dietary Guidelines, there had been 74 trials done on Low-Carb diets, compared to only 8 for the DASH diet and 1 (excluding the PREDIMED) for the Mediterranean. Most of the trials done on The Low-Carb Diet lasted longer than the trials used by the guidelines to support their 3 recommended dietary patterns. In addition, The Low-Carb Diet trials included more people than the trials used by the guidelines to support The Mediterranean, DASH and Vegetarian Diets.
Evidence Ignored by The Dietary Guidelines Committee
Many large government-funded studies were completely ignored by The Dietary Guidelines Committee. Some of these studies looked at how fat and saturated fat impact disease outcomes. These studies demonstrated that lowering fat and saturated fat do not have a significant impact on disease outcomes. Here is a summary of some of these studies:
Low-Fat Diet
Women’s Health Initiative Study
NIH- funded trial on nearly 49,000 women for 8 years.
Conclusions: Low-fat diet did not help fight obesity, cardiovascular disease or cancer.
Boeing Trials
1,230 men and women tested on the USDA diet
Conclusions– No benefit for weight loss, blood sugar control and mixed outcomes for heart disease (LDL-C dropped but so did HDL-C and TG went up).
These government conducted studies were ignored in The Dietary Guidelines. This is why The Dietary Guidelines no longer recommend a low-fat diet.
Saturated Fat
“Reduction in saturated fat intake for cardiovascular disease”
Systemiatic review and meta-analysis of randomized, controlled trials
RCTS of 59,000 participants
Conclusions: no statistically significant effects of reducing saturated fat on all-cause mortality, cardiovascular mortality, fatal MIs, non-fatal MIs, Stroke, coronary disease mortality, coronary heart disease events.
Many of these trials substituted saturated fat foods (animal foods) with vegetable oils and found little to no advantage on cardiovascular risk. Many of these trials did find that people on a vegetable oil diet had a higher risk of dying from cancer. Again, this systematic review was ignored by The Dietary Guidelines Committee.
Nina’s recommendation for change:
- Make Low Carb Diets an option- The committee members never systematically reviewed the 70 clinical trials conducted on low-carb diets. These trials demonstrate how low-carb diets are safe and helpful for people combatting chronic illness
- Make the Dietary Guidelines nutritionally sufficient- The current DGA are deficient in potassium, Vitamin D, Vitamin E and choline (largely because the Dietary Guidelines limit the consumption of animal proteins) according to the DG committee themselves. For the other nutrients, The DGA recommends that we obtain some of these other nutrients from 3-5 servings of highly refined fortified carbs. Nina argues that we should be recommending natural sources of these nutrients.
- Stop recommending lower is better on salt. Three peer-reviewed studies in major journals in addition to a 2013 report by the Institute of Medicine all conclude that in addition to an upper limit on sodium consumption, there should also be a lower limit, which a INCREASED risk of cardiovascular death is seen.
Peer-Review of The Dietary Guidelines
Nina also noted in her presentation that The US Government mandated that The Natural Academics of Sciences, Engineering and Medicine conduct a peer-review of The Dietary Guidelines of Americans. After their review, they made the following comments on The Dietary Guidelines:
My thoughts:
I agree with Nina, I think The Dietary Guidelines should be updated to be more inline with current scientific research. Since the guidelines were implemented in 1980, there has been an increase in obesity. Although this relationship between the guidelines and obesity is a correlation and not causation, we can at least recognize that the guidelines are not helping the problem. When we dive a bit deeper, we can see that the dietary patterns recommended by the guidelines do not have robust clinical trial support. We can also see that during the development of these guidelines, committee members had access to more low-carb diet clinical trials (74 trials) than Mediterranean diet (2 trials), DASH-diet (8 trials) and vegetarian diet (0 trials) clinical trials. Due to the simple fact that there is more clinical trial evidence to support the low-carb diet, I think The Dietary Guidelines should at least present The Low-Carb diets as a viable option. As new information comes to lights, its important that we change our guidelines. In fact, The American Diabetes Association has just endorsed the low-carb diet as an option.
Nina has helped open my eyes to some of the fundamental flaws in our general dietary guidelines. If you educate on nutrition or would like to learn more about the connection between nutrition and health, I highly recommend checking out her work.