The Adventist Health Study 2 was an observational study of 73,308 people. The researchers divided them into five cohorts: nonvegetarian, semi-vegetarian, pesco-vegetarian, lacto-ovo–vegetarian, and vegan. [1] Of these groups, the pesco-vegetarian had the lowest all-cause mortality, even lower than the vegans.
Of course, an observational study will always be suggestive rather than conclusive. Still, it encouraged me to give the pescatarian (or "pesco-vegetarian") diet a try.
We can identify different subcategories within the pesco-vegetarian category. My preference is to base the diet on a very low fat, whole food, plant-based diet. To differentiate my implementation from the vague "pesco-vegetarian" category, we can call it a "low-fat pesco-vegan" diet.
I began with the ideas of Dr. John McDougall. [2] This part of the diet consists primarily of starches and non-starchy vegetables.
To this I added small quantities of fish to obtain the necessary vitamin B12, ω-3 fatty acids, and other nutrients which are scarce in plant foods. By eating a little fish, you avoid the need for supplements. Also you won't end up featured on the Vegan Deterioration channel. Although a few outliers have made pure veganism work for decades, many suffer from health problems after only three or four years. Long-term vegans develop an unhealthy look of overgrown eyelids, pinched features, and a washed-out skin tone. [3]
The idea is to keep your calories from fat under 10% of your total calories. On a 2,000-calorie diet, that would mean a maximum of 200 calories a day from fat, or a maximum of 22 g of fat per day. That includes all fats, whether animal or plant, saturated or unsaturated.
Let's assume plant foods contribute 12 g of fat per day. A 3-ounce can of sardines every day would add 10 g of fat. [4] Alternatively, 8 ounces of herring would add 40 g fat, so you would have to limit yourself to one 8-ounce portion every four days.
This is a real-world experiment and not a controlled study. Once in a social situation I ate a hard-boiled egg. And one morning I had a ham-and-cheese omelette at a diner. I don't consider these incidents lapses or cheats. They are representative of the real-world conditions in which most people live.
A few days I went really hardcore and had a Kempner day. This is based on the diet for kidney patients invented by Dr. Walter Kempner in the 1940s. [5] It is designed to be low-sodium, low-protein, and low-fat. You eat only rice and fruit.
At that time there were no antihypertensive medications and no kidney dialysis machines. Dr. Kempner took patients with dangerously high blood pressures and almost completely nonfunctional kidneys, and treated them for a couple of months on his rice-and-fruit diet. Around a half of them experienced significant improvements. Their blood pressures fell, and their kidneys began to function again. Eyes damaged from retinopathy began to heal.
Dr. Kempner's patients on this restricted diet had their blood tested twice a week and saw a physician every day. In any case, Dr. Kempner only put patients on the strict version of the diet for the initial few months. After that, he introduced additional foods.
My personal implementation of the Kempner diet used Thai jasmine rice (ข้าวหอมมะลิ, khao hom mali) and oranges and bananas, which are affordable year round. Unlike the original Kempner diet, I would allow small quantities of fish. White rice has very few nutrients in it, so you are advised to take a multivitamin and multimineral if you are doing Kempner. Brown rice at least gives you some fiber and some B vitamins, but I personally find brown rice chewy and woody-tasting.
A randomized controlled trial at Stanford a few years ago showed that low-fat and low-carb diets are almost as effective as each other for weight loss. [6] In the Stanford experiment, a group of 600 people was randomized into two halves, one half on a low-fat diet, and the other half on a low-carb diet. The macros in each group were quite moderate and not as extreme as mine. After a year, both groups had lost about 12 lb. However, that was just the average. There was a huge amount of individual variation within each group. Individuals' weight losses varied from about -66 lb to +22 lb.
Despite the effectiveness of a low-fat diet for the average person, I found that the weight loss only really got going on days when I skipped lunch. This eating pattern is called two meals a day ("2MAD").
A McDougall 2MAD day with added fish might look something like this:
| Calories kcal |
Fat g |
|
|---|---|---|
| 2.5 lbs potatoes | 874 | 1 |
| 1 lb broccoli | 155 | 2 |
| 1 lb cauliflower | 114 | 1 |
| 8 oz mushrooms | 50 | 1 |
| 4 oz spinach | 26 | 0 |
| 12 oz passata | 114 | 0 |
| 1 banana | 113 | 1 |
| 1 orange | 73 | 0 |
| 3 oz can sardines | 177 | 10 |
| TOTAL PER DAY | 1,696 | 16 |
The calories and fat content of a Kempner 2MAD day with added fish might look like this:
| Calories kcal |
Fat g |
|
|---|---|---|
| Jasmine rice (2 cups raw, cooked) | 1,440 | 4 |
| 2 bananas | 226 | 1 |
| 2 oranges | 146 | 0 |
| 3 oz can sardines | 177 | 10 |
| TOTAL PER DAY | 1,989 | 15 |
Kempner is a very extreme diet and not for long-term use.
Dr. Kempner was deliberately trying to keep sodium as low as possible. To prevent cramping I wanted a normal daily intake of sodium. For this reason, and also for flavoring, I added Kikkoman wheat-free soy sauce (the one with the blue label) to the sardines.
After six-and-a-half weeks, I had lost 13 lbs. That's almost a stone in UK units of measure, or 6 kg in scientific units.
My weight loss was much more rapid than the average person in the Stanford 2018 study. Probably this is because I went very low fat (10% of calories) and because I skipped lunch on some days.
[1] Michael J. Orlich, Pramil N. Singh, Joan Sabaté, Karen Jaceldo-Siegl, Jing Fan, Synnove Knutsen, W. Lawrence Beeson, and Gary E. Fraser, "Vegetarian dietary patterns and mortality in Adventist Health Study 2," JAMA Internal Medicine, vol. 173 no. 13 (2013), pp. 1230-1238.
[2] John A. McDougall, The McDougall Program for Maximum Weight Loss (New York: Penguin Random House / Plume, 1995).
[3] https://www.youtube.com/@VeganDeterioration.
[4] All nutrient data from U.S. Department of Agriculture Food Data Central https://fdc.nal.usda.gov.
[5] Dr. McDougall's write-up of Walter Kempner and his rice-and-fruit diet is at https://www.drmcdougall.com/education/information-all/walter-kempner-md-founder-of-the-rice-diet.
[6] Christopher D. Gardner, John F. Trepanowski, Liana C. Del Gobbo, Michelle E. Hauser, Joseph Rigdon, John P. A. Ioannidis, Manisha Desai, and Abby C. King, "Effect of Low-Fat vs Low-Carbohydrate Diet on 12-Month Weight Loss in Overweight Adults and the Association With Genotype Pattern or Insulin Secretion: The DIETFITS Randomized Clinical Trial," JAMA, vol. 319 no. 7 (2018), pp. 667-679.