The Vegan Self-Experiment Part II – Results


What did I do?

I went nearly vegan for 25 days, from April 13 through May 7th, 2013, and subsequently returned to my meat-, eggs-, and dairy-heavy omnivore diet for 25 days. The vegan exceptions: I used either whey protein or BCAAs 3x per week after weightlifting, as I thought it would be important for maintaining muscle mass as my protein and calorie intake fell on a vegan diet. I also refused to suffice with the vegan omega-3 sources of ALA and SDA. I took 1 g/d krill oil for some of the good stuff: phospholipid omega 3s with an astaxanthin bonus.
For more details on the experimental motivation and procedure, see the earlier post.

Subjective qualitative findings

The two most prominent things I noticed:
Poor sleep – My sleep was noticeably worse. I had a harder time staying asleep, had less REM, and generally did not feel like my sleep was very restful. I can think of no potential confounding variable that would explain this (no added stress, work deadlines, relationship problems, change in stimulant use, etc).
Good mood – My mood was unambiguously rosier than my typical baseline. The most likely potential confounding variable that could explain this was the onset of a sunny warm spring just as I was starting veganism. This is in contrast to a cold sunless winter in the preceding months. I spent more time outside in the sun, which is usually good for my mood. However, upon returning to my omnivore diet, my mood pretty much went back to normal. This suggests causation.
Another thing I noticed after the 2-3 weeks was reduced libido. It did not fall into the toilet, so to speak, but rather went from extremely high to probably more normal levels. Actually, this was not an unwelcome change. Unfortunately, this finding is confounded by my running out of fenugreek supplements (2×550 mg/d) during the trial. In the past I have suspected that fenugreek gives a noticeable boost to my libido. This could have explained most of the difference. However, now after having resumed my previous diet, without fenugreek, my libido is higher, but still a bit below where it started, I think.

Dietary details

I logged my food intake for some representative days using myFitnessPal. I’ve made that data openly accessible. I put info for an average day into to get a more detailed nutritional profile. Here are the files: baseline, vegan, and post.
Here’s the basic summary. The “%”s are % of net calories.
  Baseline Vegan Post
“Calories” 3972 2867 3592
Net Calories 3904 2761 3516
“Carbohydrates” 171 g 252 g 216 g
Fiber 34.2 g 53.1 g 37.9 g
Net Carbs+ 146.8 g (15%) 199 g (29%) 159.1 g (18%)
Starch 72.9 g (7.5%) 92 g (13%) 85 g (9.7%)
Sugars 51.4 g (5.3%) 42.8 g (6.2%) 56.9 g (6.5%)
Sucrose 8.7 g (.9%) 13.7 g (2.0%) 11.1 g (1.3%)
Fructose 6.7 g (0.7%) 6.4 g (0.9%) 7.1 g (.8%)
Net Fructose 11.1 g (1.1%) 13.3 g (1.9%) 12.7 g (1.4%)
Fats 278 g (64%) 193 g (63%) 228 g (58%)
SAFA 144 g (33%) 95.9 g (31%) 102 g (26%)
MUFA 60.4 g (14%) 66.6 g (22%) 71.5 g (18%)
PUFA 13.7 g (3.2%) 10.9 g (3.6%) 13.9 g (3.6%)
ω-6 10.6 g (2.4%) 10.0 g (3.3%) 11 g (2.8%)
ω-3 2.2 g (0.5%) 0.9 g (0.3%) 2.1 g (0.5%)
Ratio of ω-6/3 4.8 11.1 5.2
Protein 207 g (21%) 68.2 g (10%) 182 g (21%)
amino acid score 115 75 122
Net calories = cal – 2*fiber(g)
+Net Carbs = Carbohydrates – fiber
Net fructose = fructose  + 0.5*sucrose
The lower calories post as compared to baseline is due to slightly lower meat consumption, and much lower butter consumption, with slightly higher nut consumption.

Changes in quantified metrics

“Mean” means the average value over a period near the end of the dietary regime. Spreads of two standard deviations of the sample means are given where available.
Age:30y young
Height:189cm (6’2.5’’)
Health status:Generally good, but sleep could be better.
  Baseline Vegan Post
Weight (kg) 87.9±0.5 86.0±0.3 86.7±0.4
Body fat (%) 19.0±0.7 17.9±0.6 NA
Body fat (kg) 16.7±0.5 15.4±.60 NA
Lean mass (kg) 71.2±1 70.3±.45 NA
Sleep (ZQ) 75.3±3.9 65.3±3.8 70.7±5.6
Blood Pressure      
Systolic (mmHg) 113.8±3.6 110.2±2.2 111.2±3.1
Diastolic (mmHg) 62.3±2.4 61.8±2.4 62.2±3.5
Heart Rate (bpm) 62.8±1.3 61.5±2.3 59.1±2.8
Temperature (C) 36.9±.16 36.9±.1 36.8±.09
Blood Glucose (mmol/l) 5.17±.11 5.19±.12 5.06±.13
Blood Glucose (mg/dl) 93±2 93.5±2.2 91±2.4
Temperature was taken under-the-tongue at wakeup. Weight and body fat were taken with the Withings WBS-01 Scale at wakeup (Withings advises being up and about for 30m to get an accurate body fat measurement, but this wasn’t convenient for me). The blood glucose readings were 12hr-fasted, taken in the morning, as were the blood pressure and heart rate readings. Sleep was measured with the Zeo.
Blood panels:I will update with Talking20′s full panel when they send me the results.

Blood glucose

The blood glucose data was inconclusive. 12-hr fasting levels did not change significantly: For baseline, vegan, post in mmol/l: 5.17±.11, 5.19±.12, 5.06±.13; in mg/dl: 93±2, 93.5±2.2, 91±2.4. Much more variability was seen postprandial. The vegan diet performed better at clearing a shake of 40g dextrose+25g whey after strength training, while clearance was better on the omnivore diet for a meal of 700g potato and sweet potato.

figure PPG_Dextrose.png

Figure 1 For this potato meal, blood glucose clearance was much better on the omnivore diet.

figure PPG_Potato.png
Figure 2 For a shake of dextrose and whey, blood glucose clearance was better on the vegan diet.


The max-repetitions for a few strength metrics.

  Weight Baseline Vegan Post
Pullups body weight 14 15 14
Dumbbell Bench Press 2x32kg 8 7 8
Dumbbell Standing Press 2x24kg 7 7 7
Bi-lateral Dumbbell Curl 2x24kg 7 7 7
 = Personal Record

Other subjective findings

Difficulty at home vs traveling: Being vegan while living at home was not particularly difficult for me. On the road was another matter. It’s no fun to show up to catered meals and have to turn down 90% of the food, then pull out some nuts and/or canned beans to get sufficient calories. This definitely lowers quality of life.
Fullness: I attempted to eat until full, or just beyond while vegan, as I had been doing on my previous omnivore diet. I ended up eating much less calories, as vegan food is generally more bulky. I had intended to substitute coconut oil for my previous level of butter consumption (>100 g/d), but found both coconut oil/milk to be unpalatable at those caloric levels, leading to nausea, so I consumed far less.
Strength: I was surprised that over the first 2 weeks I still made progress in the gym and even felt stronger. This could be a one-off gain from greater muscle glycogen fullness coming from my higher carbohydrate consumption (I noticed this effect to a much greater magnitude when adding carbohydrates back in after being very low carb for months). By the end of the period, I essentially was where I started, strength-wise, but had lost some kg of weight, which on the whole is not bad. I think to properly evaluate the suitability of my style of vegan diet for athletic performance and strength progression would take a longer time period to determine, and maybe more effort on my part to get a caloric excess to gain strength and mass.
Post meal state: I noticed that I generally felt physically lighter post-meal (unless I ate too much coconut milk/oil which made me nauseous for  ~ 1 hr). I also felt mentally more clear. The contrast made me more aware of how my heavy omnivore meals were impairing my thinking for a short time afterwards. Going forward, back on my previous diet, I will schedule non-taxing administrative-type work for my post-lunch period, and travel home from work in my post-dinner period. This should help maximize my productive mental capacity.
Difficulties with 16/8 IF: I rarely had hunger issues on my previous omnivore diet during the 16 hr fast that I observed daily. However, I was often hungry in the last 2 hours of the fast on the vegan diet. This could be explainable by my lower overall caloric consumption, which was sufficient to lead to a substantial rate of weight loss, or perhaps by my greater carb-dependence / loss of fat-adaptedness that very-low-carb dieters expound upon. My poor quality sleep could have been a player as well.
Is vegan sustainable for me? I would say not quite, at least not with the current level of evidence regarding its health effects. I think salmon and eggs will continue to be staples in my diet until/unless I learn of new evidence convincing me that it would be better to exclude than include them.


It’s worth underscoring the power that food-type restriction can have on energy intake, even when eating ad libitum. I’m not a big believer that calorie-counting is a particularly effective way to control net energy balance, but the discrepancy in calories between my two diets is so vast that its safe to conclude that I was taking in way less utilizable energy as a vegan, while still eating to fullness. I personally wanted to maintain, not lose (lean) weight, but for those interested in losing weight, veganism might be a hunger-free way to do it.


Here are a few of the tools I’m using to help me measure the effects of this self-experiment The most detailed nutrition measurement site that I’m aware of. Unfortunately, they don’t offer built-in day-upon-day tracking. But you can download the results to a spreadsheet and track manually. I use this upon major health evaluations to record the details of what my diet is like at that time.
MyFitnessPal Much less detailed nutritional information, but a proper tracking feature. I use this day-to-day when I want to track.
Withings WBS-01 Scale (courtesy of dacadoo) Approximates body fat via conductivity measurements across feet, and transfers info wirelessly.
Talking20 I’m a subscriber to their gold card DIY bloodwork service that delivers nice hormone, vitamin, and lipid panels.
GymGoal An iPhone app I use to track my workouts and body measurements. There’s a newer version which I haven’t tried.
Zeo Sleep Manager The only consumer-priced EEG sleep-tracking device. Unfortunately, Zeo is bust now.
Freestyle Lite Glucometer After reviewing the accuracy of many monitors, it turns out that one of the cheapest is one of the best.
Thermometer I’m sure you can find one of these.
What has your experience been with veganism/vegetarianism? Leave a comment and let us know. . .

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{ 4 comments… add one }

  • smokes 2013/06/08, 20:26

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