What the new American dietary guidelines tell us and what they left out

You might be surprised to know that nutrition understanding doesn’t radically change from one decade to the next. Nevertheless, it does evolve and the latest research was embodied in a US Advisory Report written to provide the scientific underpinnings for the 2025-2030 US Dietary Guidelines. The Report, released at the end of 2024, is impartial and rigorously scientific, but the Guidelines, which have now also been published, incorporate various stakeholder interests, undermining their validity as a definitive source of nutrition advice.  To get the unvarnished truth, we therefore need to use the Advisory Report. Its 400-plus pages are meticulously collated but don’t make the most enthralling reading. I’ve read it so you don’t have to and here are nine takeaways, including some that didn’t make it into the Guidelines.

ONE: The Report is very pro plant but the Guidelines not so much

The following from the Scientific Report Executive Summary:

“The Committee […] proposes reorganizing the order of the Protein Foods Group to list Beans, Peas, and Lentils first, followed by Nuts, Seeds, and Soy products, then Seafood, and finally Meats, Poultry, and Eggs.”

The rationale being the health benefits derived if Americans favoured this plant-first order. The underlying research is summarised in the table* below. Stick it on your fridge.

*From The Advisory Report, Part D. Chapter 2: Dietary Patterns, p. 15. The original included children and pregnant women, finding the same associations. However, as conducting experiments in these groups can be ethically dubious, the evidence was less conclusive.

However, the Guidelines, threw this ordering under the bus and the table was out too. The Guidelines (after all a joint publication between the Department of Agriculture and the Department of Health and Human Services) went with this instead: “lean meats, poultry, and eggs; seafood; beans, peas, and lentils; and nuts, seeds, and soy products”. Stakeholders, see.

TWO: Ultra-processed foods - no firm conclusions, which may disappoint.

The relationship between current public enemy No. 1, ultra-processed foods (UPFs) and weight gain was examined in the Report, finding “Limited” certainty that UPFs were linked to weight gain but also noting UPFs were generally poorly defined. Ultimately, the Report concluded the common villains of saturated fat, salt, sugar and refined carbohydrates, pervasive in UPFs, deleterious to health, and key to their moreishness, are the probable underlying culprits. Not food colouring then. Other research supports the contribution of UPFs to obesity and chronic disease also citing these factors (and lack of beneficial nutrients) as the main issue, with additives and the degree of processing potentially harmful but less well understood. (Ref)

THREE: What nutrients do Americans need more and less of?

More:

Vitamin D: Low levels in the body are certainly an issue but, even in the US where vitamin D fortification is common, sunlight, is usually the main source. (Ref)

Calcium: About  45% of American adults do not meet calcium recommendations. The Report and the Guidelines both focussed on dairy and soy alternatives to up calcium. The Report notes though that dairy often came packaged with salt (cheese), saturated fat (cheese and full fat milk) and sugar (UPFs and desserts), implying care be taken with dairy choices.

Potassium: 72% of American children and adults consume inadequate potassium, mainly attributed to shortfalls in fruit, vegetable, and whole grain intake.

Fibre: More than 90% of women and 97% of men fall short on fibre, again stemming from fruit, vegetable, and whole grain underconsumption by >85% of adults.

Less:

Linking back to the harms of UPFs, sugars, saturated fat and sodium are all being consumed in excess.

Added sugar: should be <10% of energy but it’s currently13%.

Saturated fat: should be <10% of energy but it’s currently 11%

Sodium: should be <2,300mg daily but it’s currently 3,393mg

FOUR: Who are the healthiest eaters? And who isn’t?

In a surprise to no one teen boys had the worst dietary habits, though the Report notes teen girls (second worst) will be more harmed long-term, most likely due to the impact on bone density and later risk of osteoporosis. As for the best diets, the medal goes to the over 60s, possibly as they have the time and motivation to get serious.

FIVE: Saturated fats were in focus

If you’ve read a nutrition headline on the interweb in the last few years you probably think the data linking saturated fat to disease is open to interpretation. Not so. The Report’s advice was unequivocal: saturated fat is causing harm and intakes should comprise no more than 10% of total calories- a recommendation that 66% of US adults fail to meet. (Ref) The guidelines concurred.

The Report and the Guidelines differed in their advice for how to achieve this however. The Report suggested reducing meat, eggs, full-fat dairy (particularly butter), and avoiding the plant-based saturated fats (coconut oil, palm oil and cocoa butter). The Guidelines, however went with reductions in UPFs and desserts and choosing low-fat cuts of meat. Low-fat dairy and minimising plant-based saturated fats were retained; but the suggestion to reduce eggs was removed altogether.

SIX: Dairy and Fortified Soy Alternatives

Dairy and Fortified Soy Alternatives were maintained as a separate category. It may seem heretical to suggest otherwise, but Canada, for instance, now includes dairy with protein foods. (Ref)  The Report - though not the guidelines - also implied dairy as a protein food substitute citing a “moderate” relationship between:

“substituting processed meat and red meat with dairy products and lower risk of cardiovascular disease”

As in 2020, the Guidelines category does include fortified soy alternatives but not other milk alternatives as they not nutritionally comparable. High incidence of lactose intolerance, particularly amongst the non-white US population, make soy’s inclusion a pragmatic addition. (Ref)

Interestingly, both the Report and the Guidelines continued to recommend low-fat dairy though the evidence for the superiority of low-fat over full-fat is looking increasingly tenuous. (Ref)

SEVEN: Portion size and caloric density

Answering a question you may have pondered, the Report found that children could regulate their food intake to account for larger portion sizes, though not greater food energy density. Adults, regrettably, could not regulate their food intake to account for either. This rather interesting point was cut from the Guidelines for reasons unknown.

Is there an energy density threshold that qualifies as low energy density? This was unanswered, but another study (in adults) found the cut-off amongst the third of men and women eating the lowest density diets was <1.7 cal/g (7.1 kJ/g) and <1.6 cal/g (6.7kJ/g), respectively. (Ref) To put this in context, the chart below shows the energy density of some common foods.

Data source: Nutritionix - Largest Verified Nutrition Database

EIGHT: Snacking and breakfast - yes or no?

Also thought-provoking, and included in the Report but missing in the Guidelines, was an analysis of snacking research. In adults, energy intake increased with snacking but this was due to after-dinner snacking rather than snacks at other times of the day. Consequently, evening snackers were heavier as a group than non-evening snackers, regardless of daytime snacking habits.

As for breakfast behaviours: In children, eating breakfast was linked to growth and reduced obesity, while, in adults, breakfast, whether partaken or foregone, showed no association with weight.

These results suggest that your breakfast or daytime snack habits need not unduly concern you. If you have children though, they should eat breakfast. But if you’ve read this far you probably knew that already.

NINE: Energy and nutrients - tricky to optimise

Finally, both the Report and the Guidelines noted the difficulty in meeting nutrient targets (not every day – that would be nearly impossible – but on average), while not exceeding calorie limits, assuming a diet based on a healthy version of the traditional American diet. This indicates three possible approaches:

1.      Up physical activity to allow calorie wriggle room. While offering numerous benefits, physical activity may not be a panacea, as many people offset any intentional movement by being generally (and unbeknowingly) more inert the rest of the time, perhaps explaining the weak relationship between intentional exercise and body weight. (Ref) (Ref)

2.      Pre-plan your diet to get adequate nutrients without the extra calories, continuing to select foods congruent with a healthy American diet. This is likely to involve some fairly diligent nutrient tracking. Possible. People sometimes do. But it’s work.  

3.      Remove dietary pattern constraints, that is, deviate from an American diet. Even a healthy version of it. The driver here would be a shift to lower calorie density - and likely whole - foods. Thus, foods not designed for taste and therefore generally unenhanced with sugar, sodium or fat. This can work too. It would allow consumption of more food volume, which some people like. But it may not be as tasty. Of course, it also implies more prep time; possibly, alas, more expense; and assumes such foods are available to buy in your neighbourhood in sufficient quantity and variety.

That just about wraps it up. This has been a long article but all of these topics provide rich fodder for further discussion and that’s exactly what we’ll do over the coming months. Next up: Ultra-processed foods.