The carbohydrate–insulin model of obesity posits that high-carbohydrate diets lead to excess insulin secretion, thereby promoting fat accumulation and increasing energy intake. Thus, low-carbohydrate diets are predicted to reduce ad libitum energy intake as compared to low-fat, high-carbohydrate diets. To test this hypothesis, 20 adults aged 29.9 ± 1.4 (mean ± s.e.m.) years with body mass index of 27.8 ± 1.3 kg m−2 were admitted as inpatients to the National Institutes of Health Clinical Center and randomized to consume ad libitum either a minimally processed, plant-based, low-fat diet (10.3% fat, 75.2% carbohydrate) with high glycemic load (85 g 1,000 kcal−1) or a minimally processed, animal-based, ketogenic, low-carbohydrate diet (75.8% fat, 10.0% carbohydrate) with low glycemic load (6 g 1,000 kcal−1) for 2 weeks followed immediately by the alternate diet for 2 weeks. One participant withdrew due to hypoglycemia during the low-carbohydrate diet. The primary outcomes compared mean daily ad libitum energy intake between each 2-week diet period as well as between the final week of each diet. We found that the low-fat diet led to 689 ± 73 kcal d−1 less energy intake than the low-carbohydrate diet over 2 weeks (P < 0.0001) and 544 ± 68 kcal d−1 less over the final week (P < 0.0001). Therefore, the predictions of the carbohydrate–insulin model were inconsistent with our observations. This study was registered on ClinicalTrials.gov as NCT03878108.

Paywall - https://doi.org/10.1038/s41591-020-01209-1

Full paper is on the pirate academic sites.

  • jet@hackertalks.comOPMEnglish
    2·
    1 month ago

    You will notice the Blue bar had NO reduction in fat mass. Only the red bad (lc first) had any reduction in fat mass. So clearly 2 weeks isn’t enough to say anything about anything, but it is interesting.

    Which category does water get put into? fat mass, or fat free mass? We know low carb significantly reduces water retention.

    I agree fat adaptation takes a few months. So it may not represent what happens to long term LC dieters.

    100% it does not!

    Look at the 2000 calorie day difference in intake in weeks 3/4. That does say something!

    • silly_goose@lemmy.todayEnglish
      3·
      1 month ago

      Blue bar had NO reduction in fat mass Look at the 2000 calorie day difference in intake in weeks 3/4

      What I saw in the blue bar was a reduction of body fat during the LF diet and then 2 weeks of keto undid that benefit.

      Even in the original paper the energy intake of keto dieters was high. Now it’s even higher because you trained the brain that fats are becoming scarce. (Due to fat loss from the LF diet and lack of fat in the diet itself)

      And now the brain wants to gobble up as much fat as possible.

      • jet@hackertalks.comOPMEnglish
        3·
        1 month ago

        Even in the original paper the energy intake of keto dieters was high. Now it’s even higher because you trained the brain that fats are becoming scarce. (Due to fat loss from the LF diet and lack of fat in the diet itself)

        The original paper doesn’t separate out the diet order, so we can’t rely on that analysis to tell us anything.

        We see from the separated graph that energy intake is the same during the first two weeks on both LC and LF.

        The confusion here is exactly why you need to isolate and reset between diet trials, this is the crossover effect.

        You have a interesting theory on fat scarcity and fat reuptake, it would be interesting to see it tested, but this paper does not match your theory.

        And now the brain wants to gobble up as much fat as possible. (Red line)

        We can’t say what the brain wants, this is science we shouldn’t attribute motivations we haven’t observed.

        The red line does not gobble up fat according to energy intake or fat mass.

        • silly_goose@lemmy.todayEnglish
          3·
          1 month ago

          it would be interesting to see it tested

          Same! It was a guess based on a well established principle that we crave the nutrients we lack or start losing rapidly.

          The confusion here is exactly why you need to isolate and reset between diet trials

          agree

          this paper does not match your theory

          Sorry I wrote the wrong line color again :( I will be extra careful from now on. I was explaining only the blue line the entire time.

          In the blue line people didn’t eat fat for 14 days and lost body fat. So in the next 14 days they overate and stored it back during the keto phase. (Due to increased cravings)

          edit: (more explanation) And in the red line, the subjects ate LC at the start and then switched to LF. They would have craved carbs after 14 days but they couldn’t overeat because the LF diet has a low calorie density. Fiber stretches your gut and makes you feel full.