New Research from Nature Medicine digs in
Many proponents of ketogenic diets laud it’s high fat content for keeping dieters feeling full – but how does it stack up to the high fiber of a plant-based diet?
The Basics
For many hoping to establish healthy patterns of eating while avoiding counting calories, ketogenic diets and plant based diets both seem to offer a solution – eat this type of food, not that, and the math will take care of itself. But how does this pan out in practice? A nutritional research group put these two diets head to head to find out.
To help establish how keto and plant based diets stack up when it comes to keeping you satisfied, researchers had a small group participate in each diet in a controlled setting1. They weren’t attempting to lose weight, but to evaluate how eating to satiety affected the participants. All of their food was provided for them and monitored, either 75% fat, 10% carb in the keto group or 75% carb 10% fat in the plant based group.
At the end of a two week period, the participants swapped to the other diet, so that all keto participants began their vegan diet and vice versa. An expansive array of biomarkers was tracked for all participants including weight, body fat percentage, blood pressure, cholesterol and markers of inflammation, among others.
The outcomes
plant-based dieters experienced:
42 mg/dL
reduction in total cholesterol
50%
drop in hsCRP, a marker of inflammation
23 mg/dL
reduction in LDL
1.5 lbs
fat loss over 2 weeks
while keto dieters experienced:
1 mg/dL
reduction in total cholesterol
0%
drop in hsCRP, a marker of inflammation
6mg/dL
*increase* in LDL
0 lbs
fat loss over 2 weeks
The take-aways:
01. Caloric intake and basal metabolic rate
Keto dieters ate an average of 550-700 calories per day more than the plant based group. They also burned calories at rest at a slightly higher rate, as well as while sleeping, however this was not sufficient to offset the increased intake. In the end, keto dieters lost a pound of lean mass and zero body fat, while plant based dieters lost 1.5 lbs of body fat, while eating to satisfaction.
02. Cholesterol
Impacts on LDL were striking in this study. While the effect of keto on LDL was a modest rise, plant based dieters saw an impressive 25% drop in LDL. This is approximately what one would expect from a low dose statin, despite the fact that the participants in this study did not have elevated cholesterol at the outset.
Interestingly, keto participants did see a drop in VLDL of almost 50% while mild increases were seen in the plant-based group. While VLDL is not “good cholesterol” , high LDL has strong associations with increased mortality and cardiovascular events, while VLDL does not2.
Overall the plant based group saw large reductions in both LDL and total cholesterol while keto participants maintained their baseline levels.
03. Glucose and insulin
One of the proposed benefits of a low carbohydrate diet is a hypothetical reduction in circulating insulin and blood glucose, hypothetically reducing insulin resistance. While this study did show reduced blood glucose in the keto group, (to the extent that one participant withdrew due to hypoglycemia!) both the plant based and keto participants saw comparable reductions in insulin and mild reductions in HbA1c, despite the brief duration of the study.
Final thoughts
While no single study holds conclusive answers to dietary questions, this one does a pretty good job of outlining the benefits associated with eating plant based diets, and how quickly some of those changes take place. If you’re looking for a dietary pattern that keeps you feeling full and reduces cholesterol, inflammation and body fat, it’s probably not groundbreaking news: vegetables are good for you.
Read the paper
Prefer to drink directly from the source? Check out the paper we’ve been talking about! This is a beautiful study design, so if you like details you’ll want to check it out. The second paper talks a little bit about the role of VLDL in cardiovascular health, if you’re into that kind of thing.
- Hall KD, Guo J, Courville AB, et al. Effect of a plant-based, low-fat diet versus an animal-based, ketogenic diet on ad libitum energy intake. Nat Med. 2021;27(2):344-353. doi:10.1038/s41591-020-01209-1 https://pubmed.ncbi.nlm.nih.gov/33479499/
- Heidemann BE, Koopal C, Bots ML, Asselbergs FW, Westerink J, Visseren FLJ. The relation between VLDL-cholesterol and risk of cardiovascular events in patients with manifest cardiovascular disease. Int J Cardiol. 2021;322:251-257. doi:10.1016/j.ijcard.2020.08.030 https://pubmed.ncbi.nlm.nih.gov/32810544/