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Got 10 mins? Interested in nutrition, T2DM, weight loss and cardiovascular health? What do you advise your patients? Plant based? Low carb? Keto? Confused? Join me for a Twitter journal club discussion! @ProfDFrancis @vass_vassiliou @parthaskar @KevinH_PhD @lowcarbGP @DoctorTro
Background - diet inevitably places a critical role in the development of T2DM and CV disease. Rates of obesity are soaring, which is a strong contributor to both diseases. We should be strong advocates for people eating the right stuff, preventing the disease in the first place!
But what is the right stuff? The area of nutritional ‘expertise’ is full of pseudoscience and fad diets. The DoughnutDoctor is case in point. Surely a good RCT is needed! @KevinH_PhD to the rescue!
Paper: A plant-based, low-fat diet decreases ad libitum energy intake compared to an animal-based, ketogenic diet: An inpatient randomized controlled trial. https://osf.io/preprints/nutrixiv/rdjfb/
Caveat">https://osf.io/preprints... - paper is currently pre-print but comes from the NIH (an institution we can trust).
Caveat">https://osf.io/preprints... - paper is currently pre-print but comes from the NIH (an institution we can trust).
Aim: Investigate impact of two diet protocols (vegan, mainly carb based vs keto, mainly animal based). Primary end point - mean energy intake. Secondary endpoints - weight, fat-free mass, energy expenditure, lipids, triglycerides, blood pressure and glucose tolerance testing.
Methods: RCT, crossover. 20 overweight people, without diabetes, admitted as inpatients. Importantly subjects were not informed of the purpose of the study, to avoid deliberate behavioural effects.
For 2 weeks, half ate vegan (10% fat, 75% carb, 15% protein) whilst the other half ate keto (76% F, 10% C, 14% P). Food/snacks were provided in portions of caloric excess - participants could eat as much or as little as they desired. The groups switched after 2 weeks.
Results:
Primary endpoint: energy intake lower in vegan group by 689 kcal/d.
Primary endpoint: energy intake lower in vegan group by 689 kcal/d.
Some secondary endpoints:
Favouring vegan:
https://abs.twimg.com/emoji/v2/... draggable="false" alt="✅" title="White heavy check mark" aria-label="Emoji: White heavy check mark"> Weight loss (1.09kg/2 weeks) with preservation of fat-free mass
https://abs.twimg.com/emoji/v2/... draggable="false" alt="✅" title="White heavy check mark" aria-label="Emoji: White heavy check mark"> Lower caloric intake whilst satisfaction and fullness maintained
https://abs.twimg.com/emoji/v2/... draggable="false" alt="✅" title="White heavy check mark" aria-label="Emoji: White heavy check mark"> Lower LDL-C (small effect of 0.7 mmol/l)
https://abs.twimg.com/emoji/v2/... draggable="false" alt="✅" title="White heavy check mark" aria-label="Emoji: White heavy check mark"> Better glucose tolerance test
https://abs.twimg.com/emoji/v2/... draggable="false" alt="✅" title="White heavy check mark" aria-label="Emoji: White heavy check mark"> Lower BP (3mmHg SBP)
Favouring vegan:
Weight loss (1.09kg/2 weeks) with preservation of fat-free masshttps://abs.twimg.com/emoji/v2/... draggable="false" alt="✅" title="White heavy check mark" aria-label="Emoji: White heavy check mark"> Lower caloric intake whilst satisfaction and fullness maintainedhttps://abs.twimg.com/emoji/v2/... draggable="false" alt="✅" title="White heavy check mark" aria-label="Emoji: White heavy check mark"> Lower LDL-C (small effect of 0.7 mmol/l)https://abs.twimg.com/emoji/v2/... draggable="false" alt="✅" title="White heavy check mark" aria-label="Emoji: White heavy check mark"> Better glucose tolerance testhttps://abs.twimg.com/emoji/v2/... draggable="false" alt="✅" title="White heavy check mark" aria-label="Emoji: White heavy check mark"> Lower BP (3mmHg SBP)" title="Some secondary endpoints:Favouring vegan:https://abs.twimg.com/emoji/v2/... draggable="false" alt="✅" title="White heavy check mark" aria-label="Emoji: White heavy check mark"> Weight loss (1.09kg/2 weeks) with preservation of fat-free masshttps://abs.twimg.com/emoji/v2/... draggable="false" alt="✅" title="White heavy check mark" aria-label="Emoji: White heavy check mark"> Lower caloric intake whilst satisfaction and fullness maintainedhttps://abs.twimg.com/emoji/v2/... draggable="false" alt="✅" title="White heavy check mark" aria-label="Emoji: White heavy check mark"> Lower LDL-C (small effect of 0.7 mmol/l)https://abs.twimg.com/emoji/v2/... draggable="false" alt="✅" title="White heavy check mark" aria-label="Emoji: White heavy check mark"> Better glucose tolerance testhttps://abs.twimg.com/emoji/v2/... draggable="false" alt="✅" title="White heavy check mark" aria-label="Emoji: White heavy check mark"> Lower BP (3mmHg SBP)">
Weight loss (1.09kg/2 weeks) with preservation of fat-free masshttps://abs.twimg.com/emoji/v2/... draggable="false" alt="✅" title="White heavy check mark" aria-label="Emoji: White heavy check mark"> Lower caloric intake whilst satisfaction and fullness maintainedhttps://abs.twimg.com/emoji/v2/... draggable="false" alt="✅" title="White heavy check mark" aria-label="Emoji: White heavy check mark"> Lower LDL-C (small effect of 0.7 mmol/l)https://abs.twimg.com/emoji/v2/... draggable="false" alt="✅" title="White heavy check mark" aria-label="Emoji: White heavy check mark"> Better glucose tolerance testhttps://abs.twimg.com/emoji/v2/... draggable="false" alt="✅" title="White heavy check mark" aria-label="Emoji: White heavy check mark"> Lower BP (3mmHg SBP)" title="Some secondary endpoints:Favouring vegan:https://abs.twimg.com/emoji/v2/... draggable="false" alt="✅" title="White heavy check mark" aria-label="Emoji: White heavy check mark"> Weight loss (1.09kg/2 weeks) with preservation of fat-free masshttps://abs.twimg.com/emoji/v2/... draggable="false" alt="✅" title="White heavy check mark" aria-label="Emoji: White heavy check mark"> Lower caloric intake whilst satisfaction and fullness maintainedhttps://abs.twimg.com/emoji/v2/... draggable="false" alt="✅" title="White heavy check mark" aria-label="Emoji: White heavy check mark"> Lower LDL-C (small effect of 0.7 mmol/l)https://abs.twimg.com/emoji/v2/... draggable="false" alt="✅" title="White heavy check mark" aria-label="Emoji: White heavy check mark"> Better glucose tolerance testhttps://abs.twimg.com/emoji/v2/... draggable="false" alt="✅" title="White heavy check mark" aria-label="Emoji: White heavy check mark"> Lower BP (3mmHg SBP)">
Favouring keto (mainly animal based):
https://abs.twimg.com/emoji/v2/... draggable="false" alt="✅" title="White heavy check mark" aria-label="Emoji: White heavy check mark"> More steady glucose profile (no peaks/troughs)
https://abs.twimg.com/emoji/v2/... draggable="false" alt="✅" title="White heavy check mark" aria-label="Emoji: White heavy check mark"> Higher basal metabolic rate (166 kcal/d higher)
https://abs.twimg.com/emoji/v2/... draggable="false" alt="✅" title="White heavy check mark" aria-label="Emoji: White heavy check mark"> Lower triglycerides (small effect of 0.3 mmol/l)
More steady glucose profile (no peaks/troughs)https://abs.twimg.com/emoji/v2/... draggable="false" alt="✅" title="White heavy check mark" aria-label="Emoji: White heavy check mark"> Higher basal metabolic rate (166 kcal/d higher)https://abs.twimg.com/emoji/v2/... draggable="false" alt="✅" title="White heavy check mark" aria-label="Emoji: White heavy check mark"> Lower triglycerides (small effect of 0.3 mmol/l)" title="Favouring keto (mainly animal based):https://abs.twimg.com/emoji/v2/... draggable="false" alt="✅" title="White heavy check mark" aria-label="Emoji: White heavy check mark"> More steady glucose profile (no peaks/troughs)https://abs.twimg.com/emoji/v2/... draggable="false" alt="✅" title="White heavy check mark" aria-label="Emoji: White heavy check mark"> Higher basal metabolic rate (166 kcal/d higher)https://abs.twimg.com/emoji/v2/... draggable="false" alt="✅" title="White heavy check mark" aria-label="Emoji: White heavy check mark"> Lower triglycerides (small effect of 0.3 mmol/l)" class="img-responsive" style="max-width:100%;"/>
Strengths:
https://abs.twimg.com/emoji/v2/... draggable="false" alt="✅" title="White heavy check mark" aria-label="Emoji: White heavy check mark"> Rigorous RCT design with lab controlled conditions
https://abs.twimg.com/emoji/v2/... draggable="false" alt="✅" title="White heavy check mark" aria-label="Emoji: White heavy check mark"> Meticulous measurements of calorie intake and expenditure
https://abs.twimg.com/emoji/v2/... draggable="false" alt="✅" title="White heavy check mark" aria-label="Emoji: White heavy check mark"> Vast array of secondary endpoints
Weaknesses:
https://abs.twimg.com/emoji/v2/... draggable="false" alt="❌" title="Cross mark" aria-label="Emoji: Cross mark">No wash-out period between diets
https://abs.twimg.com/emoji/v2/... draggable="false" alt="❌" title="Cross mark" aria-label="Emoji: Cross mark">Longer term implications not known
https://abs.twimg.com/emoji/v2/... draggable="false" alt="❌" title="Cross mark" aria-label="Emoji: Cross mark">Lab conditions don’t replicate everyday eating triggers e.g. seeing doughnuts at work.
Conclusions:
Bottom line on diet - we still don’t know. This paper supports the higher carb/lower fat vegan approach but the peaks/troughs in glucose profiles with higher continuous glucose monitoring readings were concerning.
Bottom line on diet - we still don’t know. This paper supports the higher carb/lower fat vegan approach but the peaks/troughs in glucose profiles with higher continuous glucose monitoring readings were concerning.
Intuitively, if one has a disorder of carb metabolism (i.e. T2DM) it would make sense to reduce carbohydrates. The keto group fared worse on the GTT but had a more stable 24-hr blood glucose profile.
Whatever diet approach you take, I think it makes sense to cut refined sugar and cut processed foods. Couple this with the laws of thermodynamics (calories in < calories out) and you will lose weight!
