Is the Protein RDA Enough? Why 0.8 Is a Floor
Quick answer: For an ordinary healthy adult who isn't dieting, the protein RDA of 0.8 g per kilogram covers basic needs. But it was built as a floor: an amount high enough that nearly everyone's minimum requirement is met. It was never designed as the best amount for someone eating less to lose weight, trying to keep muscle, or getting older. For those goals, the research points higher.
In this article
- The myth: the RDA is the recommended amount
- How the 0.8 number was built
- What 0.8 looks like in grams
- When a floor isn't the target
- What the research says
- KetoDick's take
- Key takeaways
The myth: the RDA is the recommended amount
It's in the name: Recommended Dietary Allowance. So it's easy to read 0.8 g/kg as "the amount you should eat", and anything above it as excess. You'll see that reading in articles warning that keto or high-protein eating goes "way over" what you need.
What holds up is narrower. The RDA answers one question well: how much protein keeps nearly all healthy people from falling short? It doesn't answer "how much is ideal while I'm in a calorie deficit?" Those are different questions, and they get different numbers.
How the 0.8 number was built
Here's the mechanism behind the number, in plain words. Researchers measure how much protein people need to stay in nitrogen balance, meaning they aren't losing more body protein than they take in. Everyone's need is a little different, so you get a spread.
A large meta-analysis of those nitrogen-balance studies found a median requirement of 0.65 g/kg/day, with the 97.5th percentile at 0.83 g/kg/day (Rand, Pellett & Young, 2003). In other words, half of people need less than 0.65, and almost everyone's need is covered by about 0.83.
That's how you set a floor. The US/Canada RDA of 0.80 g/kg/day sits on top of an estimated average requirement of 0.66 (National Academies DRI report). Europe's population reference intake, 0.83 g/kg/day, sits on an average requirement of 0.66 (EFSA, 2012), and the WHO's safe adult intake is also 0.83 (FAO/WHO/UNU, 2007).
The RDA is a "nobody comes up short" number. It's a minimum, set generously.
What 0.8 looks like in grams
Back-of-envelope, for a 70 kg (154 lb) woman:
- RDA: 0.8 × 70 = 56 g a day. Over three meals, under 19 g each.
- Lower end of the weight-management range below, 1.2 g/kg: 1.2 × 70 = 84 g a day, or 28 g a meal.
- KetoDick's beginner rule for most women: 80 g a day (video UygKGoP_BtA).
So the gap between "floor" and "practical target" for most readers is about 25 to 30 g a day. That's roughly one extra serving of protein, not a steak-at-every-meal lifestyle.
When a floor isn't the target
The RDA assumes a healthy adult at a steady weight. Several situations move you off that assumption:
- Eating in a deficit. When you eat less, your body has more reason to draw on lean tissue. Trials of energy-restricted diets found that higher protein protected more fat-free mass (see What the research says).
- Wanting to keep or build muscle. Strength training raises the useful amount. The sports-nutrition range starts well above 0.8.
- Getting older. Expert groups writing for older adults recommend more than 0.8, while the WHO kept one adult number without a separate higher value for older people. That's a real disagreement among the bodies, not a settled point.
- Appetite. Protein helps you feel full. If hunger is what knocks you off a plan, the floor isn't doing you any favours.
So what you do is treat 0.8 as the line you shouldn't drop below, then set your actual target from your goal. For most women losing weight, that's somewhere around 1.2 g/kg of goal weight, or KetoDick's 80 g as a shortcut.
What the research says
- The floor: RDA 0.80 g/kg/day, estimated average requirement 0.66 (National Academies); median need 0.65, 97.5th percentile 0.83 (Rand et al., 2003).
- Higher intakes are commonly eaten: EFSA describes intakes up to about twice its 0.83 reference as regularly consumed and considered safe (EFSA, 2012).
- Weight management: about 1.2 to 1.6 g/kg/day, with 25 to 30 g per meal, associated with better appetite and weight management (Leidy et al., 2015).
- Muscle in a deficit: 24 trials, 1,063 people; energy-restricted high-protein diets gave modestly more weight and fat loss and less fat-free-mass loss (Wycherley et al., 2012).
- Older adults: 1.0 to 1.2 g/kg/day for those over 65 (PROT-AGE, 2013); at least 1.0 to 1.2 g/kg/day for healthy older adults, alongside physical activity (ESPEN, 2014).
- Kidneys: across 28 studies (1,358 people), higher protein did not change kidney filtration differently in adults without kidney disease (Devries et al., 2018). If you do have kidney disease, that finding doesn't cover you: set protein with your doctor.
KetoDick's take
He's been pushing against protein fear for years. In his 2018 beginners' video he said the community has "a huge inappropriate fear of protein" (from the video), and that too little protein can mean poor body composition and muscle loss, so err high (video UygKGoP_BtA). When a Men's Health piece described keto as limiting protein to 100 g, he answered that he knows plenty of people in ketosis who eat more than that, and that protein is "a target, not a limit" (from the video) (video 1JbK1_ClDmY).
He doesn't cite the RDA by name. His numbers simply start where the floor ends: 80 g for most women and 100 g for men, with more for tall or athletic people (video UygKGoP_BtA).
Key takeaways
- The RDA, 0.8 g/kg, is a floor built to cover nearly everyone's minimum need.
- It wasn't designed for people eating in a deficit, training, or trying to protect muscle as they age.
- For a 70 kg woman, the floor is about 56 g; a practical weight-loss target is closer to 80 to 85 g.
- Intakes well above the RDA are common and, in adults without kidney disease, didn't change kidney filtration in the studies.
- With kidney disease, your doctor sets the number.