The Curbsiders podcast

#360 Disease-Modifying Nutrition with Dr. Michelle McMacken

October 17, 2022 | By


The treatment your patients need but may not be getting!

Take a bite out of our latest episode featuring guest expert Dr. Michelle McMacken (@DrMcMacken) and learn how you can help your patients effectively and sustainably reap the health benefits of improved nutrition. Discover the enormous evidence base for nutritional recommendations, develop scripts to engage patients, and update your CVD, T2DM, and hyperlipidemia treatment plans to meaningfully incorporate nutrition. Get your truffle-hunting outfit on, it’s time to go foraging for some tasty knowledge food! 

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  • Written and Produced by: Deep Shah MD
  • Show Notes:  Sarah Phoebe Roberts, Deep Shah MD
  • Infographic and Cover Art: Lyan Chang
  • Hosts: Matthew Watto MD, FACP; Paul Williams MD, FACP; Deep Shah MD
  • Reviewers:  Emi Okamoto MD
  • Showrunner: Matthew Watto MD, FACP
  • Technical Production: PodPaste
  • Guest: Michelle McMacken MD, FACP, DipABLM

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CME Partner: VCU Health CE

The Curbsiders are partnering with VCU Health Continuing Education to offer FREE continuing education credits for physicians and other healthcare professionals. Visit and search for this episode to claim credit. 

Show Segments

  • Intro, disclaimer, guest bio
  • Guest one-liner, favorite advice
  • Case from Kashlak; definitions
  • “Evidence-based nutrition” vs plant-based diet
  • Unifying the guidelines for patient care
  • Treating the skeptical patient
  • Tailoring recommendations to patients’ needs 
  • Treating the motivated patient
  • Host questions
  • Outro

Nutrition for the Internist: Pearls

  1. Suboptimal diets are the leading risk factor for dying of a chronic disease in the US and globally (US Burden of Disease Collaborators, 2018)
  2. Ask your patient if they’re interested in talking about how the foods they eat influence their health. If they’re interested, proceed; if not, try circling back at a future visit.
  3. Help your patient set very specific, realistic behavior change goals (e.g. “I will have old-fashioned oatmeal (or overnight oats!) three mornings a week.”)
  4. There is strong and consistent evidence that these foods promote health and are linked to LOWER risk of chronic disease and cancer: vegetables, whole fruits, legumes, whole grains, nuts, seeds, and fatty fish rich in omega-3 fatty acids. 
  5. There is strong and consistent evidence that these foods are linked to HIGHER risk of chronic disease – especially cardiometabolic conditions – and cancer: processed meats, unprocessed red meat, added sugars, refined grains, and ultra-processed foods. 
  6. Avoid using nutrient terms like carbs, protein, and fat. These terms can be confusing and imprecise. Instead, name the specific types of foods you recommend eating more or less of.
  7. Emphasize adding healthy foods to the diet and crowding out less-healthy foods, rather than focusing only on what someone should avoid.

Disease-Modifying Nutrition Show Notes

What is evidence-based nutrition?

Research on nutrition and chronic disease

There is an enormous body of literature regarding the effects of diet and nutrition on health outcomes. The evidence base includes RCTs as well as prospective cohort studies, metabolic ward studies, and other research methods with varying strengths and limitations. Dr. McMacken recommends looking for overlap and unifying themes in the literature. There are decades of science to refer to, and over time certain questions and claims have accumulated enough evidence to be considered reliable and even unequivocal (Hauser, 2022). 

Overarching themes and unifying results

Some categories of food have consistently been found to be health-promoting and associated with a lower risk of chronic disease and cancer. These include: vegetables, whole fruits (not juices), legumes (beans, lentils, peas, chickpeas, tofu, tempeh, edamame), whole grains (oats, whole wheat, brown rice, barley, etc), nuts, seeds, and fish that are rich in omega-3 fatty acids (Belardo, 2022, ACC/AHA Guidelines 2019). There is very little controversy about these foods and it is very hard to find any studies showing they are harmful.  

A few caveats about fish / omega 3 fats:

  • Only 1-2 servings of fish per week are needed to get the benefits.
  • Caution advised with regular intake of larger fish that are higher in mercury. 
  • Omega 3 fats can also be obtained from non-fish sources such as ground flaxseeds, hemp seeds, walnuts, and chia seeds. EPA and DHA can be obtained from algae-based omega 3 supplements (fish get their omega 3s from algae). 

There is also strong and consistent evidence that certain foods are linked to higher risk of chronic disease, especially cardiometabolic conditions, and cancer (Belardo, 2022, ACC/AHA Guidelines 2019):

  • Processed meats (any meat that has been smoked, salted, fermented, or has added sodium: sausage, ham, bacon, pepperoni, cold cuts, deli meats, etc.)
  • Unprocessed red meat (e.g., beef, pork, lamb, etc.)
  • Added sugars (as found in sugar-sweetened beverages, most commercial breakfast cereals, many breads, desserts, many ultraprocessed foods)
  • Refined grains (e.g., white rice, “white” breads, rolls, crackers, and other foods made with processed grains; note that “multigrain” does not mean whole grain – it usually means multiple refined grains)
  • Ultraprocessed foods (e.g., most commercial snack foods, chips, crackers, etc.)

The literature and guidelines are generally in consensus that processed meat of any type is associated with an increased risk of cancer (particularly colorectal cancer), heart disease, and T2DM. Unprocessed red meat has also been linked to elevated cancer, T2DM, and heart disease risk (Wolk, 2016). Ultraprocessed foods are especially a concern because they are very calorie dense, hyperpalatable, lack fiber, and have additives not found in nature.  

The evidence is more complicated for the below foods. Some studies show benefit, particularly when these foods are compared with unhealthier foods; some studies show potential for harm.

  • Dairy: wide variety of health effects with spectrum of foods (eg, unsweetened yogurt is very different from butter). High-fat dairy (eg, whole milk, butter, cheese, ice cream, etc.) tends to raise LDL cholesterol due to its saturated fat content.
  • Poultry
  • Eggs
Specific impacts of nutrition on health and mortality
Can better nutrition really reduce morbidity and mortality? 
Suboptimal diets are the leading risk factor for dying of a chronic disease in the US and globally.  (US Burden of Disease Collaborators, 2018). However, incremental improvements in diet quality are linked to significant benefits. A 20-percentile improvement in diet quality is significantly associated with an 8-17% reduction in total mortality. (Sotos-Prieto, 2017). Similarly, an additional serving of fruit per day has been linked to an 8% decrease in cardiovascular mortality, which would translate into 60,000 fewer deaths/year in the US. (Kahan, 2017)  Fruit is truly the low-hanging fruit of nutrition counseling!
Healthier eating patterns that focus more on plant-based foods and less on processed foods have been shown in many prospective observational studies to improve health outcomes. Although these studies are not RCTs and a causal link cannot be established, there is a strong and consistent association with improved outcomes. For example, if you compare animal versus plant sources of protein, there are at least five very large prospective cohort studies suggesting that just substituting very small amounts of your calories from animal protein with a plant source comes with an associated mortality benefit (Sun, 2021; Huang, 2020; Song, 2016).  Plant-based diets also have a role for preventing and improving diabetes, including through substituting animal protein for plant-based proteins (Viguiluouk, 2015; Malik, 2016). 
With the proliferation of processed plant-based foods, it is important to note that not all plant-based diets are created equally. Just because something is technically vegan or plant-based in that it lacks animal products/protein does not necessarily mean that it is healthy (e.g. potato chips and soda). Some vegan/vegetarian processed foods (e.g. plant-based meats) may have high levels of sodium and saturated fats while other vegan/vegetarian products contain added sugars that increase T2DM risk.

Talking to patients about diet and nutrition

Starting the conversation

Dr. McMacken describes feeling a sense of ethical duty to address nutrition with her patients when it could potentially benefit them, e.g. for patients with elevated A1C or LDL. Most patients think that their physicians are a credible source of nutrition information, so your word can go a long way! Start by asking your patient if they’re interested in talking about how the foods they eat influence their health. If they’re interested, proceed. If they’re not, respect that and try circling back at a future visit. If the patient is lukewarm about making any dietary changes, try to set a small goal that’s appropriate but feels manageable and sustainable for both the patient and their household. If the patient is not the person in their household who does most of the food preparation, Dr. McMacken will invite  the patient to bring the person who does to the appointment.

Name the foods the patient eats, and the foods the patient likes

If a patient is willing to talk about nutrition, Dr. McMacken recommends asking the patient for a 24-hour dietary recall (ie, what did you eat and drink yesterday, starting from the time you woke up). This is never fully accurate but it does give you a quick and useful snapshot – you can even ask the patient to complete the food/beverage recall while in the waiting room to save time or utilize other validated rapid diet screeners (AHA, 2020).

TIDBIT: Don’t forget to ask about ginger ale! Some people  do not consider ginger ale to be a soda/sweetened beverage.

From the list above (or the SuperFoods handout), ask your patient about healthful foods they already happen to like. Work within their cultural traditions. Most culinary traditions incorporate many healthy foods – it is a matter of moving these to the center of the plate. Emphasize adding healthy foods to the diet and crowding out less-healthy foods, rather than focusing only on what someone should avoid. Avoid using nutrient terms like carbs, protein, and fat as they can be confusing and imprecise. The term “carbs” lumps many healthful carb-containing foods (e.g., lentils and oats) with unhealthful carb-containing foods (e.g., lollipops, white breads, processed crackers, etc.). Instead, name the specific types of foods you recommend eating more or less of. 

Helping your patients meet their nutrition goals

Meet the patient where they’re at

Dr. McMacken  recommends helping your patient set very specific, realistic behavior change goals, e.g. “I will add a serving of broccoli to my plate three times this week, and a different vegetable next week” or “I will have old-fashioned oatmeal (or overnight oats) three mornings a week.” Highly motivated patients may be able to work on having one healthy meal per day. The key is to let the patient tell you what they’re ready to work on and then set a SMART goal. Additionally, write down the plan on paper or put it in the after-visit summary so that the patient has a copy. Use online resources and partner with a registered dietitian if possible.

Tailor your recommendations to the patient based on their unique needs, preferences, and abilities. Encourage simple swaps, especially diversifying protein sources to include more plant proteins, such as legumes. This can look like lentil bolognese or black bean tacos. Help your patient change the food environment in their home (e.g., working with their family not to keep sugar-sweetened beverages in the house). For patients who are more enthusiastic about modifying their nutrition, you can set additional goals (e.g., going from eating a healthy breakfast twice a week to three times) or drill down further. If the  patient has switched out an animal protein for a plant source, it may be appropriate to discuss which plant-based-protein options are optimal. When it comes to any macronutrient, it’s not so much about the quantity  in your diet, it’s about where you’re getting it from. In the case of fats, are those coming from healthier sources like nuts, seeds, avocados and olive oil? Very different from fats found in bacon, butter, and other foods that are very rich in saturated fat (AACE/ACE, 2020). 

TIDBIT: the saturated fats in coconut oil, for example, can raise LDL if consumed in excess (Neelakantan, 2020).

Offer food insecurity screening as a routine, and get a sense of the patient’s barriers – low cooking skills, time/family pressures, financial/access challenges, etc. Eating healthfully doesn’t have to be very expensive, though it often requires the time to plan in addition to any financial cost. Legumes (dried or canned beans/lentils), whole grains, and frozen veggies are all relatively inexpensive and extremely nutritious. Try to troubleshoot through barriers and set some new goals. You’ll get faster and better at this the more you do it!

Following up with patients

Manage expectations

Set reasonable expectations. Reassure the patient if they express disappointment that they haven’t met a specific goal (e.g., weight loss, glycemic control, etc.). Emphasize that improvement can taketime as they transition to new habits. For patients who are not prepared to make significant changes in the near future, there is a compelling reason to initiate medication / pharmacotherapy at the onset of a cardiometabolic diagnosis for those who would benefit. If, however, the patient is making major changes, often they can either avoid medications or lower their doses to achieve disease remission through diet and lifestyle change (ACLM, 2022).

Celebrate small victories!

The patient may not need or want to switch to a healthy or plant-based diet overnight, but small diet shifts can have an outsized health benefit. 

If the patient DOES switch to a completely plant-based diet, as with any eating pattern it’s important to ensure nutrient needs are being met. B12 supplementation is essential on a fully plant-based diet. There are several reliable online resources for physicians and patients on plant-based diets. . 

On follow-up visits, celebrate any nugget of progress. Remember that any movement along the spectrum towards a healthier diet is likely beneficial, even if it is not a dramatic change. It’s about progress, not perfection!

Other Stuff


  1. Succession (HBO show)
  2. Guy Fieri (American restaurateur, frosted tips icon)

Resources for patients


Listeners will recognize that nutrition is an evidence-based therapeutic tool in treating T2DM, hyperlipidemia, hypertension, and other cardiometabolic conditions.

Learning objectives

After listening to this episode listeners will…  

  1. Recognize that nutrition plays a critical role in cardiometabolic health and is a core component of many professional society treatment guidelines with a robust literature base
  2. Develop compelling scripts to engage patients in making dietary shifts to lower their cardiometabolic risk
  3. Update treatment algorithms (and templates) for at least one medical condition to incorporate nutrition in a meaningful way 


Dr. McMacken has no relevant disclosures. The Curbsiders report no relevant financial disclosures. 


Shah D, McMacken M, Williams PN, Watto MF. “#360 Disease Modifying Nutrition with Dr. Michelle McMacken”. The Curbsiders Internal Medicine Podcast. October 17, 2022.


  1. October 18, 2022, 12:46am Sean Curran writes:

    I had to stop listening at the beginnings of this interview. Dr. McMacken sounded more like an activist than a scientist or clinician. She made no reference to healthy user bias in any of the studies she mentioned. Although I could not listen to the whole episode, I wonder if she made any mention of the poor oral bioavailability of plant proteins. How exactly are eggs unhealthy? The ACC/AHA recently recognized dietary cholesterol (but not saturated fat) has no effect on blood lipids. Terrible.

    • November 23, 2022, 10:22am Ask Curbsiders writes:

      Hi, we realize nutrition is a hotly debated topic. We will do further nutrition episodes featuring other points of view!

  2. October 28, 2022, 3:01pm Alison Krzesniak writes:

    I adored this episode. Nutrition is vital yet neglected by a majority of people (including myself!). I've been doing my own research on this topic so I was very excited to listen in. I would love to see more lifestyle medicine and even functional medicine topics. Digging deeper into nutrition, perhaps an episode on some of the common diets today would be useful (keto, intermittent fasting, etc.). Thank you sincerely for all you do. I love to hike and always listen to one or two of your podcasts to get some exercise and learn at the same time. Alison Krzesniak FNP-C

    • November 19, 2022, 10:48pm Ask Curbsiders writes:

      We are so glad you enjoyed this one! We have shared your show pitch with the rest of the team! Best of luck to you.

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The Curbsiders are partnering with VCU Health Continuing Education to offer FREE continuing education credits for physicians and other healthcare professionals. Visit and search for this episode to claim credit.

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