DGA vs AHA: Why Nutrition Guidelines Disagree

Bret: 
Welcome to the Metabolic Mind Podcast. I’m your host, Dr. Bret Scher. Metabolic Mind is a non-profit initiative of Baszucki Group where we’re providing information about the intersection of metabolic health and mental health and metabolic therapies, such as nutritional ketosis as therapies for mental illness.

Thank you for joining us. Although our podcast is for informational purposes only and we aren’t giving medical advice, we hope you will learn from our content and it will help facilitate discussions with your healthcare providers to see if you could benefit from exploring the connection between metabolic and mental health

Why does it seem like we can’t agree on what’s healthy to eat? Why does it seem we’re always arguing about this? Turns out, there’s a lot we do agree on. And we can compare the new dietary guidelines for Americans from HHS and the newly released dietary guidelines for heart health from the AHA. Now, these two guidelines share definite similarities.

Don’t get me wrong, they differ in key ways as well. And that’s important because it can leave us feeling confused and unclear who to believe, right? And back to this argument of what’s healthy to eat. So, let’s talk about where they’re similar, where they’re different, but most importantly, why they differ, as that may help us better understand who we want to side with because as individuals. That’s what we should care about, right?

Which way of eating is better for me as an individual? So, let’s start with what they get right and where they align. So, both the HHS for the Dietary Guidelines for America, the DGA, and the American Heart Association, they emphasize reducing added sugars, limiting refined grains, cutting back on ultra-processed foods, and focusing on whole, minimally processed foods.

This is a major area of agreement. And if most of the population adhered to those principles, we’d be in a much different place in terms of our collective health, right? But regardless of whether someone prefers a higher carb or a lower carb diet, reducing highly processed foods, reducing sugars, refined grains, those are some of the most consistent ways to improve overall health.

And that’s one part of our collective diet that has gotten it really out of control over the past few decades. Despite the watchful eye of organizations like the AHA and other medical organizations, our collective health has really deteriorated because we haven’t adhered to those principles. But beyond that shared foundation, the approaches really begin to diverge.

One thing that appears clear is that the HHS guidelines take a more flexible approach. They acknowledge that both animal-based and plant-based foods can be part of a healthy diet, depending on the individual, the dietary makeup, et cetera. And there are plenty of studies to support that framework. In contrast, the American Heart Association leans much more strongly towards recommending a shift away from animal foods towards predominantly, if not fully, plant-based eating patterns.

And there are studies to support this recommendation as well. But the question is, what studies, right? Most of these studies, most of this evidence, I should say, rely heavily on observational studies, nutrition epidemiology, which as we know, can show associations and even at that, often weak ones, but with low-quality data that don’t prove cause and effect. And we’ve talked about the low-quality of this data many times.

Those studies often don’t fully account for differences in lifestyle, food quality, overall dietary patterns, and so forth. So, to take this quality of evidence and assume it applies to all of us is simply misguided and using the evidence for, I guess you can say, far more definitive purposes than it really is equipped for.

And that’s one reason why I appreciate the HHS’s more inclusive approach, rather than the AHA’s restrictive approach. Another key difference, though, is how each framework approaches individual variation. So, the DGA, they explicitly recognize that diet should be individualized. They highlight factors like metabolic health, personal preferences, cultural background, lifestyle, all these things that they all play a role in determining what works best for someone. And we know that different people respond differently to different diets, especially when you look at metabolic health as the primary goal.

In contrast, the American Heart Association tends to emphasize a more uniform approach, focusing heavily on reducing LDL cholesterol as their primary target. And this is where the philosophies really differ. The AHA places a strong emphasis on lowering LDL cholesterol, and they have for decades, recommending reducing saturated fat and reducing animal-based foods to achieve that goal.

But LDL is just one marker of health. It doesn’t always capture the full picture of health, especially metabolic health. So, what about markers of insulin resistance, like fasting insulin levels, triglycerides, HDL, body composition, and many others? All of these provide key insights into someone’s overall health and their cardiac risk beyond LDL. And they’re going to be impacted differently by different diets.

So, the DGA acknowledges this broader view by emphasizing metabolic health and individual responses rather than focusing on more of a single lab number. Yet, the AHA continues to strongly recommend limiting saturated fat and openly discourages foods, like red meat and full-fat dairy, despite the fact that the evidence is more mixed than many people realize.

So, some studies can show associations between saturated fat and cardiovascular disease while many others do not find a clear link, especially when excluding low-quality epidemiology studies and when looking at whole foods rather than processed food diets. Now remember, both HHS and AHA agree on eating whole foods and reducing sugars and reducing refined grains. And it turns out when we do that, saturated fat-containing foods and animal-based foods likely don’t have the negative health impacts that we see in these epidemiology studies. But that nuance isn’t emphasized in the AHA guidelines.

And a perfect example of this is full-fat dairy. So, the AHA guidelines strongly recommends against full-fat dairy and instead choosing low-fat dairy products. But at the same time, if you actually read that section, the dairy section in their publication, they acknowledge that the evidence does not show that low-fat dairy is superior for health outcomes. Yet, the recommendation remains.

So, it’s fair to ask why would the AHA recommend avoiding full-fat dairy while at the same time acknowledging the evidence does not clearly support it? I think it’s clear that just old beliefs die hard, and much of these recommendations are actually opinion-based and not based on solid evidence.

And that’s okay as long as they’re clear about that. And remember, it’s not like the DGA says we should all eat meat and avoid plants. They clearly state we should get protein from whole food plants and whole food animal sources, and that reflects both science and real world experience. Something the AHA seems to discount, this real world experience.

Now, it’s easy for me to point out the differences, but here’s the key. This matters for people. It really matters and probably for you because it can be confusing. The DGA says one thing. The AHA is saying something with real important differences. How do you as an individual know who you should listen to?

in addition, beyond that, the dietary guidance shapes what doctors recommend, what schools teach, and basically, what our culture believes is healthy. So, there are real consequences to getting this right. And one last point, this whole discussion only matters if people can actually follow the recommendations.

If recommendations are too rigid or too one-size-fits-all, they may not work for everyone. In fact, there may be very few people who they actually work for. And in a way, that’s the experiment we’ve run over the past few decades, which hasn’t worked out too well for our overall and metabolic health. It’s clear we’re just not eating in a healthy manner.

So, the takeaway isn’t that one framework is entirely right and the other is entirely wrong. It’s that nutrition is more complex than a single universal prescription. Both the HHS guidelines and the AHA agree on the importance of reducing processed foods, refined grains and sugars, and improving overall diet quality.

But the HHS approach reflects a growing recognition that there is more than one way to eat well. And that individual variation, metabolic, cultural, personal, it matters. Health and nutrition advice shouldn’t be about choosing the one best diet, but about helping people find the one that works best for them.

So, don’t be confused. Understand where the guidelines agree. Understand not just where they differ, but why they differ. Obviously, I think my bias shows, I suggest siding more with the HHS, the DGA for all the reasons I’ve mentioned here. But you may still wish to side with the AHA recommendations, and that’s fine as long as you understand there is a choice and you understand the differing philosophy about that choice.

I think that’s the key.

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