New study: weight loss doubled without ultraprocessed foods

Nutrition Q&A [Moderated]
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Nature study (open access): Ultraprocessed or minimally processed diets following healthy dietary guidelines on weight and cardiometabolic health: a randomized, crossover trial | Nature Medicine

NYT writeup: https://www.nytimes.com/2025/08/04/well/eat/avoiding-ultraprocessed-foods-might-double-weight-loss.html (accessible view: https://archive.ph/W7zbv)

I hadn’t seen this covered here. I know the doctors emphasize energy as the ultimate baseline regardless of amount of processed food in the diet. However, the practical implications seem to warn against allowing high prevalence of ultraprocessed products in one’s food environment even with an eye towards total calories, because of the difference in satiety. The study includes protein bars and powders as among the products that contribute to relatively higher cravings. I think the findings are a reason to seek all or most of your macros from solid whole foods, but I wonder about the realistic prospects of achieving the recommended dose of protein, for example, without adding ultraprocessed sources. I wonder if others think, e.g., one serving of protein powder per day is advisable to reach desired macros without minimizing appetite suppression to a suboptimal degree.

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Yea, this paper came out ~ 4 days ago and we haven’t had a chance to cover it just yet. It’s likely to be in our next research review though. I will say I don’t really like the NYT write-up, but what else is new.

I don’t really agree with the idea that protein powder contributes to higher cravings and overall energy intake, especially given the mountain of evidence to the contrary. I don’t feel the same about protein bars, though there’s so much variability in the quality of protein bars and how people use them that I wouldn’t label them as good or bad either.

As far as people obtaining the recommended dose of protein without ultraprocessed foods, I think it’s pretty easy given that the average intake of protein is quite high at baseline at ~ 1.1g/kg/day. Most people would need an extra 1 to 2 servings of protein per day to exceed the 1.6g/kg/d target, which doesn’t seem like too much of an imposition.

However, the relatively high baseline protein intake is predominantly from foods that are processed :joy: My perspective on how increased protein intake improves dietary quality and weight outcomes is that the entire dietary pattern changes to include more protein from minimally procesed sources, which displaces foods that are ultra-processed in the “bad” way, e.g. they have added sugars, added sodium, and or added fat. Adding a protein supplement on top of this would have effectively no negative influence on cravings or hunger based on available data.

My take on the study are as follows:

  • pretty much any significant change in the diet can lead to weight loss in the short-term
  • “double the weight loss” is a sensational headline, despite neither group losing much weight at all. I don’t think it’s reasonable to extrapolate these results out longer term.
  • Labeling foods processed or not is probably not very helpful/meaningful. Instead, should likely call out specific processing elements by name that DO have a reliable effect, e.g. “added sugar”

Just my 0.02

-Jordan

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