What does research tell us about the advice in the new US nutrition guidelines?

Sharon M. Donovan is a professor of nutritional sciences and the Melissa M. Noel Endowed Chair in Nutrition and Health, whose work centers on childhood obesity prevention and optimizing health throughout the lifespan. Donovan, who was a co-creator of the previous federal Dietary Guidelines for Americans released in 2020, spoke with News Bureau research editor Sharita Forrest about the 2025-2030 guidelines that were released last week.

The new guidelines are briefer than prior editions, and while some say they are more user-friendly for lay audiences, critics say they lack enough specificity or have incorrect information. Are the new dietary guidelines grounded in science?

One area of concern is the alcohol recommendation. The new dietary guidelines replaced the limit on one drink per day for women and two for men with the recommendation to “consume less alcohol.”

However, a review by the National Academy of Sciences that was commissioned by the U.S. Congress to inform the 2025–2030 Dietary Guidelines for Americans concluded that alcohol intake clearly increases cancer risk, even at low levels of consumption. The evidence linking alcohol to increased risk of several major cancers — breast, colorectal, liver, esophageal, oropharyngeal, and laryngeal — is strong and consistent.

The surgeon general’s 2025 advisory report states that “alcohol consumption is a leading preventable cause of cancer, that risk increases even at low levels and that there is no threshold below which risk is zero.” It appears that neither of these reports was incorporated into the new guidelines.

The new guidelines prioritize consumption of full-fat dairy and animal protein. Are these changes healthy and practical?

There are a few issues to consider here. First, dairy and meat are nutrient-rich foods and have been included in previous dietary guidelines. What differs in the 2025 guidelines is the recommendation to consume higher-fat meats and full-fat dairy, whereas previous versions recommended lower fat options. The new guidelines also prioritize oils rich in essential fatty acids and using butter and beef tallow when adding fats to meals. These recommendations have received the most attention from nutrition and medical professionals, given the associations of high saturated fat intake with cardiovascular disease.

While the 2025 guidelines encourage consumption of higher-fat meats and full-fat dairy, they also recommend limiting saturated fat to no more than 10% of calories, similar to earlier versions of the guidelines. This is where the numbers may not add up.

Let’s do the math. For a 2,000-kcal diet, 10% of calories is 200 kcals, or 22 grams of saturated fat, since fat has 9 kcals/gram — more than twice as much as protein and carbohydrates.

Full-fat dairy has 4.5 grams of saturated fat per serving, so three servings per day will provide about 14 grams of saturated fat, leaving only 8 grams from other foods to stay within the guidelines. However, butter has 7 grams of saturated fat per tablespoon, fatty meats can have up to 30 grams per 4 ounces, and eggs have 1.6 grams each.

Thus, it will be very challenging to eat more high-fat foods while keeping saturated fat at 10% of calories.

The guidelines strongly recommend reducing highly processed foods due to their adverse impact on the gut microbiome and overall health. What does research say about consuming these foods?

Dietary fiber is most associated with promoting gut health and a healthy microbiome. Over 90–95% of U.S. adults fail to meet daily fiber targets. Average intake is 14–16 grams per day, while recommendations are 25 and 38 grams daily for women and men, respectively.

Highly processed foods tend to be low in fiber and high in refined carbohydrates. The best dietary sources of fiber are fruits, vegetables and whole grains. The new dietary guidelines recommend three vegetables, two fruits and two to four servings of whole grains daily. This will provide 22–30 grams of fiber. Choosing higher-fiber options such as berries, pears, oats and barley can help you get closer to the goal.

Questions have also been raised about the recommendations on essential fatty acids – i.e., that they cannot be consumed and are only made by the body. Is this correct?

Actually, it is the other way around. Essential refers to nutrients that the body cannot make; that is why they are essential to consume in the diet. Linoleic acid (LA, n-6 fatty acid) and alpha-linolenic acid (ALA, n-3 fatty acid) are the only two essential fatty acids. Olive oil contains a moderate amount of LA compared with soybean or sunflower oil and a very low amount of ALA. Butter is very low in both LA and ALA, while lard provides some LA.

Following the new guidelines could result in low intakes of essential fatty acids, particularly ALA. Flaxseed or chia seeds, with 5-7 grams per tablespoon, are good plant sources of ALA. While fatty fish do not provide much ALA, they do contain two healthy fatty acids — DHA and EPA, which the body — ours or the fish — makes from ALA.