I’ve been thrilled to see the new U.S. Dietary Guidelines pivot back toward real food.
However, one of the most controversial residual issues is the 10% limit on saturated fat.
I recently heard RFK Jr. describe the saturated fat cap as the most contentious issue during development of the guidelines, suggesting he would have preferred it removed. I’ve also seen many other experts express similar reservations.
But the real debate isn’t actually about saturated fat.
It’s about what we choose to measure, prioritise, and optimise in our food.
My view — as detailed in previous articles — is that macronutrient balance becomes largely irrelevant when nutrient density is the guiding principle. The same applies to subfractions of macronutrients, such as saturated fat, sugar, and polyunsaturated fat.
The problem arises when we worship or demonise a single food parameter. Those fixations on ‘bad things’ often throw everything else out of balance and dilute nutrient density.
As you’ll see in this article, when we instead focus on increasing intake of vitamins, minerals, and amino acids, sensible guardrails for fat, carbs, and energy intake tend to emerge naturally.
Nutrient Density: The Metric That Actually Matters
While the 2020 to 2025 US Dietary Guidelines mentioned nutrient density, the new 2025 to 2030 guideline puts it in the spotlight.
If You Don’t Measure It, You Can’t Improve It
Unfortunately, however, nutrient density is still a very poorly defined term. To manage something effectively, you have to measure it.
As an engineer who fell down the nutrition rabbit hole more than 10 years ago, I’ve spent a ton of time quantifying nutrient density and guiding tens of thousands of people to achieve it in real life in our 20/20 Macros and 20/20 Micros courses.
Why “Adequate” Nutrition Isn’t Enough
Unfortunately, the Dietary Reference Intakes (DRIs), EARs, and AIs aren’t much help because they are the minimum required to prevent deficiency-related diseases.
If you want to thrive, not just survive, you need to set a target for nutrient intakes that you can strive towards for maximum health, satiety, and vitality.
That’s why we created the Optimal Nutrient Intakes (ONIs), which are the level of nutrient intake (per calorie) where the (satiety) benefit of getting more of that nutrient diminishes.
In our system, a meal, a day of eating, or a week of eating that provides 100% of the Optimal Nutrient Intakes for all 34 essential nutrients receives a diet quality score of 100%.
The charts below demonstrate how we calculate the diet quality score and how we show Optimisers in our 20/20 Micros class how to use the food they already eat to boost their diet quality. Basically, if you meet the ONI for all 34 essential nutrients, you receive a diet quality score of 100%. A little quantification turns nutrition into a game where the goal is to fill the nutritional gaps in your diet with real food.
Optimisers who achieve a high diet quality score aren’t following a specific named diet or taking handfuls of supplements every day. They’re just eating a range of minimally processed real foods that provide plenty of all the essential nutrients they need to thrive.
To increase their nutrient density, Optimisers don’t have to overhaul their diet; they just eat more of the foods they already know and love and a little less of others. Only later, if they want to really level things up, can they add new foods to address their current nutritional gaps.
Getting 100% isn’t easy — or even necessary for most people — but it’s a fascinating challenge to learn to level up your nutrition using data.
Why Saturated Fat Became the Villain
The 2015 -2020 US Dietary Guidelines quietly dropped cholesterol as a nutrient of concern to avoid or restrict after the committee acknowledged that the latest research showed no clear link between dietary cholesterol and cardiovascular disease.
However, even the latest guidelines still retain the 10% limit on saturated fat, which goes back to 1990. Even RFK Jr wasn’t able to delete it from the latest edition.
But why?
The indirect logic is that replacing saturated fat with polyunsaturated fat lowers LDL-cholesterol, which is associated with coronary heart disease risk.
To be clear, there are no studies that show a biological inflection point where more saturated fat leads to reduced overall mortality. 10% saturated fat was just seen as roughly the average US population intake, and targeting less than 7% has shown poor adherence in trials.
Saturated Fat Intake in the Real World
The frequency distribution chart below shows the range of saturated fat intake across 477k days of data from tens of thousands of people following a wide range of diets.
The average across all these data points is 11.8%, which is similar to the NHANES survey, which shows 11-12% saturated fat. Just 44% of the data points fall under the arbitrary 10% saturated fat target imposed by the dietary guidelines. That means the majority of the population is apparently doing it wrong, according to this limit.
When “Healthy Fats” Stop Being Healthy
Interestingly, the intake of monounsaturated fat shows a similar distribution. But the guidelines impose no limit on the more plant-based fats because they’re seen as ‘good fat’.
However, as detailed in Monounsaturated Fat: Is it So Good For You After All?, the USDA data shows that per-person daily fat intake has increased by around 700 calories, with most of that coming from monounsaturated and polyunsaturated fats. Scarily, this increase in our intake of ‘good fats’ has paralleled the increase in obesity rates.
This is not due to Mediterranean dieters adding olive oil to their salads. Instead, it’s more likely due to the increase in seed oils used as cheap, nutrient-poor ingredients in ultra-processed foods engineered to hit our nutrient bliss points.
While the intake of monounsaturated fat has increased, the intake of saturated fat has decreased in percentage terms.
To be clear, I’m not trying to argue that saturated fat is better than monounsaturated fat. I just don’t think we need to put an arbitrary limit on saturated fat while effectively giving monounsaturated fat a free pass.
Saturated Fat and Appetite Regulation
From a satiety perspective, saturated fat and monounsaturated fat have a similar profile. More fat from either source aligns with increased energy intake. I could even argue that the data suggest that reducing MUFAs and PUFAs (the ‘good fats’) has a greater satiety benefit.
Howver the real problem really comes when we mix energy sources in ways that do not occur in nature. If your diet is dominated by one source of fat, you’ll actually eat less. The problem comes when we stack a moderate amount of saturated fat, with a moderate amount of monounsaturated fat, with some sugar, and some flour, with minimal protein and fibre. This combination of energy sources appears to create an irresistible, low-satiety, nutrient-poor cocktail that we can’t stop eating.
This helps explain why so many people feel hungry and unsatisfied even though they think they’re “eating healthy”.
Saturated Fat Intake on a High-Quality Diet
When you focus on getting the nutrients you need from your food, you don’t need to worry too much about anything else. But we can examine the ranges of X, Y, or Z intake that correspond to a higher diet quality score.
Saturated Fat
As shown in the chart below, if you really want to max out nutrient density, aiming for 6-13% saturated fat is the sweet spot. Push your saturated fat too low, and you’ll struggle to get enough protein and all the nutrients associated with it. Push it too high, and you’ll dilute your nutrients per calorie.
In this context, the 10% saturated fat target of the dietary guidelines should really be seen as a stretch target for maximum nutrient density and increased satiety for those wanting to maximise nutrient density and lose weight, not a baseline limit for the general population who just want to be healthy and maintain their weight.
Monounsaturated Fat
For monounsaturated fat, the optimal range is a bit higher, but not by much.
Stop Micromanaging Fat. Start Maximising Nutrients.
When you focus on protein, vitamins, and minerals per calorie, the rest of the diet largely self-regulates.
Foods that deliver a high proportion of essential nutrients per calorie tend to:
- be naturally higher in protein,
- come packaged with minerals and vitamins,
- and land in sensible ranges of both saturated and monounsaturated fat, not to mention sugar, fibre, carbs, and fat.
In this context, obsessing over saturated fat versus monounsaturated fat misses the point. It can actually be a distraction that can be counterproductive to achieving greater satiety and nutrient density.
When nutrient density is high, you don’t need to micromanage fat subtypes — nutrient density creates the guardrails.
Optimising micronutrient intake per calorie naturally increases protein intake, reduces ultra-processed food intake, and helps balance your appetite because you’re getting the nutrients your body craves to thrive.
Rather than treating the <10% saturated fat target as a hard limit, it’s better viewed as a stretch target for people who want to max out nutrient density and lose weight, not as a baseline target for the general population who don’t want to lose weight.
The real problem isn’t saturated fat. It’s nutrient-poor, ultra-processed foods that combine multiple energy sources without the protein, fibre, vitamins, and minerals that drive satiety.
Focus on nutrients first — and the rest will look after itself.
If a food helps you hit protein, minerals, and vitamins with fewer calories, you’re moving in the right direction — regardless of its fat profile.