In my ideal world, people wouldn’t be arguing about carbs vs. fat, sugar vs. starch, or saturated fat vs. monounsaturated fat.
Instead, the simple focus would be on getting enough of what actually matters: protein, vitamins, and minerals.
But the renewed debate around saturated fat limits in the latest real-food-focused US dietary guidelines got me thinking. While obsessing over individual nutrients isn’t helpful, there are some data-driven guardrails for the energy-containing nutrients that clearly align with good, better, and optimal nutrient density.
Based on data from hundreds of thousands of days logged by our Optimisers, the table below summarises those ranges.
Protein is the primary driver, but there are clear ranges for carbs, fat, fibre, and net carbs that consistently align with higher diet quality.
| Parameter | Good | Better | Optimal |
| Protein (%) | > 21% | > 32% | 51% |
| Total Fat (%) | < 70% | 14–42% | 28% |
| Total Carbs (%) | < 52% | 13–26% | 19% |
| Saturated Fat (%) | – | 6–13% | 9% |
| Net Carbs (%) | < 38% | 6–69% | < 38% |
| Monounsaturated Fat (%) | – | 12–25% | 18% |
| Fibre (g / 2000 kcal) | – | > 33 g | 67 g |
Protein: The Main Lever
The chart below shows the relationship between protein percentage and Diet Quality Score, using 178,000 days of real-world data from our Optimisers.
The spline curve (with 99.9% confidence bands) makes the message unambiguous:
Higher protein intake strongly aligns with higher diet quality.
That said, how much protein is “enough” depends on your goal.
Are you simply maintaining health? Trying to lose fat? Or aiming for optimal nutrient density?
Here are some practical protein targets you can use as training wheels:
- Good (>21% protein) – Getting more than 21% of your energy from protein puts you ahead of 75% of our Optimisers. This is a solid baseline for maintaining weight and health if you’re reasonably active.
- Better (>32% protein) – A powerful yet achievable target if you want to improve nutrient density, lose some weight, and feel more energetic. This places you ahead of about half of our Optimisers.
- Optimal (~51% protein) – This aligns with maximum nutrient density but is a challenging stretch. Push much higher, and you may crowd out essential fats and micronutrients—even though amino acid intake remains high.
One of the most important changes in the new US dietary guidelines is the focus on prioritising protein, raising the target from 0.8 g/kg to 1.2–1.6 g/kg of body weight per day.
If you’re interested in increasing protein without overdoing the energy, check out our protein-rich food list and infographics in our community resources section here.
Total Carbohydrates: Less, but Not Zero
As protein intake increases, refined carbohydrates naturally decline.
For general maintenance, any carb intake below 50% of total energy works well. But if your goal is to increase nutrient density, the sweet spot tends to be 13 – 26% of energy from carbohydrates.
Plant-based foods can provide complementary vitamins and minerals that are harder to obtain from meat, dairy, and seafood alone, so some carbs are usually better than none for satiety and micronutrient coverage.
Fibre: The Silent Accelerator
Once carbs are moderated, fibre becomes an important secondary lever.
As shown in the data, diet quality continues to improve, with fibre intake reaching ~67 g per 2000 kcal.
That’s ambitious, so a more realistic starting point is 33 g / 2000 kcal – enough to put you ahead of half of our Optimisers.
Fibre adds bulk, slows digestion, improves satiety, and tends to travel with micronutrients—making it, along with a higher protein %, one of the most reliable upgrades you can make.
Nutrient-dense vegetables tend to be packed with fibre, rich in nutrients, and low in energy.
Net Carbs: A Better Target Than Total Carbs
Like protein and fibre, net carbs are a poor source of energy. If your goal is to improve satiety and nutrient density, managing net carbs is often more effective than tracking total carbs.
- < 38% net carbs works well for maintenance
- 8–20% net carbs aligns with higher nutrient density
- 14% net carbs corresponds with maximum diet quality.
Those managing blood glucose may prefer the lower end of this range.
Fat
Fat is usually the last lever people adjust—and often the hardest.
In our 20/20 Macros course, the biggest challenge isn’t carbs—it’s getting enough protein while dialing back excess fat.
- < 70% fat is fine for maintenance, especially if carbs are low
- 14–42% fat aligns with better nutrient density than half of our Optimisers
- ~28% fat consistently tracks with optimal diet quality
But Which Fat Is “Best”?
People love debating good fats vs bad fats, but in practice, the only truly problematic fats are those that add energy without nutrients.
This often shows up as:
- Refined seed oils added to ultra-processed foods
- Large amounts of butter, cream, or MCT oil (which add energy that people don’t really need).
Most whole foods contain a mix of fats. Meat and dairy tend to be high in saturated fat, while plant foods tend to be higher in monounsaturated and polyunsaturated fats.
The data suggests that optimal nutrient density tends to occur between:
- Monounsaturated fat between 12–25% of energy
- Saturated fat between 6–13% of energy
This likely reflects food choices more than physiology or cravings. Plant-heavy diets skew higher in mono fats; meat- and dairy-heavy diets skew higher in saturated fat.
If protein and carbs are in a good place, you don’t need to micromanage fat types.
How to Implement This (Without Losing Your Mind)
I’m not a fan of obsessing about limiting carbs, fats, saturated fat, sugar, or anything else.
Most people don’t want to track food forever—and rigid limits often create more fear and confusion than clarity.
Instead of focusing on what to avoid, I’d rather people prioritise what reliably improves satiety and nutrient density: Protein and/or fibre (i.e., real foods with micronutrients).
In our 20/20 Macros program, Optimisers learn how to eat more of the foods they already enjoy—while naturally increasing protein percentage and nutrient density.
In 20/20 Micros, we take it further, identifying which foods fill specific nutrient gaps.
You don’t need perfection to get started. But if you want to manage, let alone optimise anything, a little quantification goes a long way.