Wei Perng, PhD, MPH

For years, type 2 diabetes (T2D) has been treated as a single disease. If someone has high blood sugar but does not meet criteria for type 1 diabetes or another form of diabetes, they are diagnosed with T2D. But researchers are starting to rethink what we call “type 2 diabetes” as multiple distinct conditions that all lead to elevated blood sugar.

Why one size does not fit all.
As discussed in a recently published commentary, not everyone develops T2D in the same way. For some individuals, the problem starts with insulin resistance (when the body stops responding to insulin properly). This is often associated with obesity. For others, their bodies don’t produce enough insulin, sometimes due to genetics and/or environmental factors that damage the pancreas. These differences matter and provide hints on the sequence of biological events that culminate in disease. A study in European populations suggest that these differences may help explain why some T2D patients manage their diabetes with lifestyle changes, others require medications, and some develop serious complications – like kidney or heart disease, or even early mortality. Identifying distinct root causes, as well as the progression of biological events responsible for high blood sugar is key to the effective prevention, treatment, and management of T2D – and can look very different from person to person.

The DEFINE-T2D Consortium.
To better understand this complexity, the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) launched the Definition, Etiology, Function: INtegration to Enhance T2D treatment (DEFINE-T2D) Consortium in 2024. This large research effort brings together data from 13 observational cohort studies, 4 randomized controlled trials, and 6 electronic health record systems and biobanks. Together, these resources include information from more than 4.8 million individuals, many with prediabetes or established T2D. The scale of the project gives researchers an unprecedented opportunity to better understand different forms of T2D. DEFINE-T2D researchers are examining multiple layers of information, including traditional clinical measures (such as blood sugar levels, blood pressure, weight, and medications), genetics (inherited risk factors), omics data (a catch-all term for advanced lab measures using proteins (via proteomics) and metabolites (via metabolomics) to uncover disease pathways at the molecular level).

Researchers are also looking beyond biology. The analyses will also integrate these “below-the-skin” factors with “above-the-skin” influences (known as environmental and social factors) including things like access to education, health care, and grocery stores or indirect exposures including diet, exercise, sleep, and stress. By combining all of this, DEFINE-T2D investigators hope to identify distinct T2D subtypes and determine whether they each carry their own risks for complications and comorbidities.

What does this mean for clinical care?
If researchers can identify distinct forms of T2D, it could change how we approach care for those who are at high risk of or have the disease. Clinicians may eventually be able to predict how their patient’s disease will progress more accurately and choose treatments that work best for that specific individual. A better understanding of T2D subtypes will also help identify high-risk patients earlier and offer tailored prevention strategies. This approach, called precision medicine, moves away from a one-size-fits-all model and towards more personalized care.
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Why this matters.
T2D affects hundreds of millions of people worldwide, yet the effects of this disease vary from person to person. Understanding why is one of the most important next steps in precision diabetes research. The DEFINE-T2D Consortium represents one of the largest efforts ever undertaken to better understand the biology of T2D. While the work is still in its early stages, it has the potential to reshape the prevention, diagnosis, treatment, and management for T2D patients, and lead to better outcomes for people living with this chronic disease.

Food insecurity or inconsistent or inadequate access to enough food for a healthy life is a well-documented social determinant of health. But it is not experienced equally across the population. Our new preliminary research using the Massachusetts Statewide Food Access Survey reveals a striking picture: in 2024, more than half of LGBTQ+ adults in the Commonwealth were food insecure, and many are not using the systems designed to help.

​A Persistent Disparity
Using data from 9,169 Massachusetts residents surveyed between 2022 and 2024, we measured food insecurity with the 10-item USDA Household Food Security Survey Module. Among LGBTQ+ adults, food insecurity rose from 45% in 2022 to 56% in 2024, significantly higher than non-LGBTQ+ adults each year. These numbers are staggering, though not entirely surprising. A 2017 Williams Institute analysis found that 26.7% of American LGBTQ+ adults experienced food insecurity in the prior year, roughly double the national average. Furthermore, LGBTQ+ adults are about twice as likely to experience poverty compared to non-LGBTQ+ adults, a direct consequence of the historical and ongoing discrimination and stigma that likely drives high rates of food insecurity.

Many Aren't Getting Help
Beyond measuring food insecurity, this study examines whether LGBTQ+ adults are using available assistance. In 2024, only one-third used food pantries, and fewer than half used SNAP (the Supplemental Nutrition Assistance Program). LGBTQ+ adults reported multiple barriers to pantry access more frequently than non-LGBTQ+ adults. For example, many pantries are housed in religious settings that haven't always been welcoming to LGBTQ+ people. Transgender and gender nonconforming individuals may face additional, concrete obstacles when applying for benefits if they are unable to receive accurate identification documents. More broadly, discrimination and stigma in housing, employment, and healthcare can make it harder to trust the systems meant to help. Even SNAP, which offers more privacy than visiting a pantry in person, poses barriers and proposed federal policy changes that would make access harder.

Why This Matters and What Can Be Done
Food insecurity isn't just about hunger; it has cascading effects across physical and mental health. The association of food insecurity with poor health outcomes, including mental illness and chronic diseases, has been well-documented, but research has increasingly called for closer examination of how food insecurity affects LGBTQ+ individuals specifically. Given that LGBTQ+ adults already face elevated rates of depression, anxiety, and other chronic conditions, the added burden of food insecurity is particularly dangerous for their health outcomes.
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Our forthcoming research findings show that addressing food insecurity among LGBTQ+ adults requires more than just making programs available. We need multi-level interventions that are designed with input from LGBTQ+ communities themselves to address the unique barriers they face and begin to minimize the burden of food insecurity in this population.

Author
Austin R. Waters is a postdoctoral fellow through the Dana-Farber Cancer Institute and the Harvard LGBTQ Health Center of Excellence. He received his PhD in Health Policy and Management from the University of North Carolina at Chapel Hill. His research focuses on prevention, access, and outcomes among LGBTQ+ and adolescent and young adult (AYA) patient populations. The common threads of his research revolve around health equity, health-related social needs, economic instability, cost-related barriers to care, the influence of policy, and technology use. 

Hilary Dolstad, MD

​Eating well is important at any stage of life, but during pregnancy, nutrition becomes key to supporting a developing baby. Plant-based (also known as vegan) diets have increased in popularity in recent years due to their associated health benefits, as well as environmental and ethical concerns. In fact, from 2019 to 2020, U.S. retail sales of plant-based foods rose by 27%, reflecting the growing popularity of plant-based diets. This raises a question for some expectant parents: what do we know about the impact of a plant-based diet during pregnancy?

​A 2024 systematic review examined the research on vegan diets and birth outcomes, identifying just six relevant studies. Since this is still an emerging area of research with limited evidence, there were no definitive conclusions—but here’s some of what researchers have found so far:

• Many outcomes were similar between people following vegan diets and those with omnivorous diets.
• Maternal weight gain was lower among those on a vegan diet in the two studies that looked at this outcome.
• Gestational diabetes and preterm birth rates did not differ significantly between the two groups in any of the studies.
• Infant birth weight was lower in some of the studies among those on a vegan diet, but this finding was not consistent between all the studies.
• Preeclampsia was higher in one small study, but this study included only 18 vegan participants, and other studies did not note this trend.

Overall, it appears that few studies have directly examined the relationship between a vegan diet during pregnancy and birth or pregnancy outcomes, and the studies so far are small. Five of the six studies had 60 or fewer vegan participants, and none were randomized controlled trials, which would be gold standard for determining causal relationships. These limitations may help explain the inconsistent results. It’s also possible that any observed differences could be due to indirect factors, such as protein intake or caloric intake, which could be optimized within a well-planned vegan diet.

Given the rise in popularity of plant-based diets, hopefully there will soon be more data in this area. For now, the best guidance remains the same, regardless of underlying dietary patterns: recommendations include consuming sufficient folic acid, as part of a balanced diet rich in vegetables, fruits, healthy grains and proteins. 

Author
Hilary Dolstad is a fellow in General Internal Medicine and Primary Care. She received her medical degree from Harvard Medical School and completed combined residency training in internal medicine and pediatrics at Brigham and Women’s Hospital and Boston Children’s Hospital. Prior to her medical training, she worked in public health on the local and national level. As part of the Harvard Fellowship in General Internal Medicine and Primary Care, her research focuses on maternal and child health, including environmental factors and policies that influence health in the perinatal period and throughout the life course. She is currently an MPH candidate at Harvard T.H. Chan School of Public Health. Clinically, she is interested in primary care for adults and children.

Kat Lynch, MPH

​Grocery shoppers can often get swept up in the bright colors and healthy promise of fresh produce, only to watch it wilt as the week gets busy. It’s an unpleasant experience opening the refrigerator to find spoiled fruits and vegetables you meant to eat, especially when improper storage can speed up the process. What many people don’t realize is that frozen produce is often just as nutritious, if not more, than fresh options that have spent days sitting on the shelf.
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​Fresh fruits and vegetables naturally lose nutrients over time as they are exposed to oxygen, light, and temperature changes. Freezing, however, acts like a pause button, locking in nutrients right after harvest. Most frozen fruits and vegetables are picked at peak ripeness and then blanched (or briefly boiled) before freezing, which helps preserve vitamins and minerals. Frozen options are also affordable, available year‑round, and often pre‑chopped, making healthy cooking easier for busy schedules. The key is checking ingredient labels, since some frozen produce contains added sauces or sugars. Choosing plain frozen fruits and vegetables ensures consumers get the most nutritional value.
 
Despite these advantages, many people still view frozen produce as less healthy and less appealing than fresh ones. Perhaps this is because food beliefs are often shaped by biases rather than facts. People may attach moral meaning to foods, viewing “natural” as good and “processed” as bad. Similarly, labels like organic, vegetarian, or gluten-free can create a “halo effect,” that makes foods seem automatically better based on one positive attribute. Fresh produce benefits from this same “halo effect,” even when the nutritional value is equal to – or in some cases, lower than – its frozen counterparts.
 
One study tested this bias by asking people to evaluate spinach labeled as fresh or frozen. When shown only in the packaging, participants rated the “fresh” spinach more positively than frozen. However, when they saw the final cooked dish, the difference disappeared. Why? The fresh spinach looked less appealing after cooking, while the frozen spinach did not change once cooked. The preference was psychological, not nutritional. There’s a false belief that freezing is a “transformation” that reduces naturalness, even though it effectively preserves nutrients.
 
Misconceptions about frozen foods can discourage people from eating enough fruits and vegetables, especially among groups who would benefit most, including those in low-income households. In fact, in one study of participants in Supplemental Nutrition Assistance Program Education (SNAP-Ed) and Expanded Food and Nutrition Education Program (EFNEP) classes, 94% bought frozen produce at least occasionally for its convenience and long shelf life, yet many still believed fresh produce had better flavor, texture, appearance, nutritional value, and fewer preservatives. Broader national data also reinforce these patterns – income, education, and having children under 18 strongly predict frozen produce purchasing, and SNAP participants are especially likely to buy frozen vegetables, suggesting frozen options may be particularly valuable for households seeking affordable, long‑lasting foods. Together, these findings highlight the need for targeted nutrition education that emphasizes the nutritional equivalence, cost savings, and practical benefits of frozen produce.
 
Ultimately, our focus should shift away from trying to debate whether fresh or frozen is better, and instead consider what helps us eat more fruits and vegetables overall. Frozen options are just as nutritious as fresh, last longer, reduce waste, and offer flexibility. That convenience makes healthy eating more realistic and affordable. In the end, the best produce is the kind you will actually eat – whether it comes from the fridge or the freezer.

​The nation’s updated five‑year 2025-2030 Dietary Guidelines for Americans introduce several notable updates, including a redesigned food pyramid and a renewed emphasis on whole foods and protein. The changes have sparked debate among researchers, clinicians, and public health professionals. Beyond the headlines, the more important question is how recent evidence informed these recommendations, and what they may mean for chronic disease prevention and federal nutrition programs moving forward.

Unprocess Your Plate
One of the most significant shifts is the clearer emphasis on limiting highly processed foods. For the first time, the guidelines explicitly discourage packaged, ready-to-eat products high in added sugars and refined ingredients. This change reflects a growing body of research linking diets high in ultra-processed foods to obesity, type 2 diabetes, cardiovascular disease, and overall mortality.
A recent meta-analysis reported consistent associations between higher ultra-processed food consumption and increased risk of cardiovascular disease and other adverse cardiometabolic outcomes. While earlier editions focused primarily on individual nutrients such as added sugars or sodium, the current guidance more directly acknowledges the role of food processing and overall dietary patterns in shaping health outcomes. This evolution reflects decades of research supporting dietary patterns centered on whole and minimally processed foods, such as vegetables, fruits, whole grains, legumes, nuts, and healthy fats that protect against chronic disease.
The guidelines also continue to reinforce limits on added sugars and encourage greater intake of fiber-rich whole foods. The updated guidance emphasizes nutrient-dense foods and overall dietary quality, rather than focusing narrowly on calorie counts. These recommendations remain consistent with long-standing evidence from the Mediterranean diet and the DASH diet, both linked to improved cardiometabolic health and reduced risk of chronic disease.
The Protein Pivot
Another prominent feature of the new pyramid is its prioritization of protein. The guidelines highlight protein consumption across the lifespan, with attention to muscle maintenance and metabolic health. National data from What We Eat in America (NHANES) indicate that most U.S. adults already consume an adequate or high amount of protein, though adequacy varies by age and sex. This context has prompted experts to debate how broadly to interpret higher protein targets, and whether that messaging could distract from other important components of a balanced diet. Because guidelines still advise limiting saturated fat to less than 10% of daily calories, careful communication is essential to ensure that increased attention on protein does not create confusion around high-saturated fat sources, such as certain red or processed meats. Messaging should also highlight protein-rich options like legumes, seafood, nuts, and low-fat dairy.
Nuanced Nutrition and Forming the Foundation for Federal Programs
These nuances do not diminish the broader strengths of the guidelines. Rather, they illustrate the complexity of translating evolving nutrition science into clear, population-level recommendations. Faculty experts at Harvard T.H. Chan School of Public Health have noted that while the guidelines maintain important advances, particularly in discouraging ultra-processed foods, certain aspects, including the prioritization of animal protein sources over plant-forward options, have generated discussion about alignment with elements of their Advisory Committee’s scientific report.
Importantly, the public health implications of the Dietary Guidelines extend beyond individual dietary choices. The guidelines serve as the foundation for federal nutrition programs, including SNAP, WIC, the National School Lunch Program, and the Child and Adult Care Food Program. The updated guidelines can influence food procurement standards, nutrition education, and meal planning across programs serving millions of Americans. Even modest, widespread improvements in diet can help reduce obesity, cardiovascular disease, diabetes, and other chronic conditions.
Ultimately, the impact of the 2025-2030 Dietary Guidelines depends less on the design of a pyramid, and more on how well the recommendations are translated into practice. Aligning federal policy, food environments, and clinical guidance with the strongest available evidence offers an opportunity to strengthen prevention efforts nationwide. Thoughtful implementation and clear communication will determine whether these updates translate into measurable improvements in population health.

Author 
​Nelly Miranda Mongalo, MPH, is a public health professional with a concentration in Health Services Management & Policy. She earned her Master of Public Health from Tufts University School of Medicine, where her work focused on nutrition policy analysis and early childhood health initiatives. Her interests include maternal and child health and chronic disease prevention. As a foreign-trained dentist who transitioned into U.S. public health, she brings a clinical perspective and a population-level approach to health policy. Nelly is passionate about advancing policies and programs that support healthier families and communities. Outside of her professional work, she enjoys traveling and spending time on family adventures with her husband and two daughters.