This short and free read, I’d recommend getting your hands on it immediately; you’re given a clear description from William Banting himself (1796 – 1878) about how he went from obese to normal weight in a matter of months. He was ~67 years old at the time of his n=1 personal experiment…
Here I’m going to share some of the notes I’ve taken from Banting’s booklet – that details his journey -, a writing he dedicates to the public at large, “entirely from an earnest desire to confer a benefit on my fellow creatures.” 
You can read it for free here.
Notes from Banting’s N=1
Banting’s physical characteristics (measurements) before dieting – as of August 1862:
– 66 years old, 5 feet 5 inches tall, weight of 202 lbs.
At the end of the same year, he had already lost 42 pounds and 12 inches from his waist.
He assumes his unhealthy weight was not due to ignorance, but due to daily (excessive?) consumption of certain foods:
“My corpulence and subsequent obesity was not through neglect of necessary bodily activity, nor from excessive eating, drinking, or self-indulgence of any kind, except that I partook of the simple aliments of bread, milk, butter, beer, sugar, and potatoes more freely than my aged nature required.” 
He later ‘rationalized’ that these types of foods may be useful occasionally but detrimental as a ‘constancy’. Thus, upon advice, he decided to abstain as much as he could from the consumption of “bread, butter, milk, sugar, beer, and potatoes, which had been the main (and, I thought, innocent) elements of my existence, or at all events they had for many years been adopted freely.” 
In brief, Banting reports:
“My former dietary table was bread and milk for breakfast, or a pint of tea with plenty of milk and sugar, and buttered toast; meat, beer, much bread (of which I was always very fond) and pastry for dinner, the meal of tea similar to that of breakfast, and generally a fruit tart or bread and milk for supper. I had little comfort and far less sound sleep.” 
His ‘day of eating’ according to his new regimen consisted of:
– 4-5 oz of: beef, kidneys, broiled fish, mutton, bacon, or cold meat (of any kind except pork)
– I assume he had a total of 4-5 oz of a combination of these protein rich food, and not 4-5 oz. of each (?)
– unsweetened cup of tea, a ‘fit tie’ biscuit or 1 oz of dry toast
– 5-6 oz of: any fish other than salmon, any meat other than pork
– any vegetable except potatoes
– “one ounce of dry toast, fruit out of a pudding, any kind of poultry or game.” 
– 2-3 glasses of wine; he forbade himself the consumption of champagne, port (wine?) and beer.
For ‘tea’ (is that ‘snack’?):
– 2-3 oz. fruit
– a rusk or two (from the dictionary: “a slice of sweet raised bread dried and baked again in the oven”)
– unsweetened cup of tea
– 3-4 oz of meat or fish
– 1-2 glasses of wine
“For nightcap, if required, a tumbler of grog – (gin, whisky, or brandy, without sugar) – or a glass or two of claret or sherry.” 
From what I see, this lad was having a lot of ‘fun’ while shedding pounds. No wonder he reported having 6-8 hours of ‘excellent night’s rest’. He is also ‘careful’ to mention:
“The dry toast or rusk may have a table spoonful of spirit to soften it, which will prove acceptable. Perhaps I did not wholly escape starchy or saccharine matter, but scrupulously avoided those beans, such as milk, sugar, beer, butter, &c., which were known to contain them.” 
Some particularities of his new diet:
– he didn’t favor pork consumption because of its ‘fattening character’
– he didn’t favor the consumption of oily fish (salmon, herrings and eels)
– during his drastic weight loss period, he abstained not only from consuming potatoes, but also from eating parsnips, beetroot, turnips, and carrots
“Green vegetables are considered very beneficial, and I believe should be adopted at all times. I can now also state that eggs, if not hard boiled, are unexceptionable, that cheese, if sparingly used, and plain boiled rice seem harmless.” 
Some time after being embarked on his diet, Banting recalls not having felt so good in the last 20 years.
“Go up stairs and take ordinary exercise freely, without the slightest inconvenience.
Can perform every necessary office for myself.
The umbilical rupture is greatly ameliorated, and gives me no anxiety.
My sight is restored—my hearing improved. My other bodily ailments are ameliorated;
indeed, almost past into matter of history.” 
I think it’s safe to assume that such improvements could be due to both his new diet and the process of weight loss itself.
One year after embarking on his diet, in September 1863, William Banting, 46 pounds lighter (weighing 156 lbs) felt quite confident ‘cheating’ on his diet:
“I am now in that happy comfortable state that I should not hesitate to indulge in any fancy in regard to diet, but if I did so should watch the consequences, and not continue any course which might add to weight or bulk and consequent discomfort.” 
“Feeling that I have now nearly attained the right standard of bulk and weight proportional to my stature and age (between 10 and 11 stone), I should not hesitate to partake of a fattening dietary occasionally, to preserve that happy standard.” 
Along the same lines, Banting reports that he has frequently indulged his fancy in using milk, sugar, butter, and potatoes, with the careful observation that these were exceptions (frequent exceptions?) not the rule.
This is quite different to what I am used to hearing and seeing all over the place -everyday-: folks blaming themselves for slightly and temporarily falling off their self-imposed dietary restrictions. Friends, don’t do that!
I may not be surprised of Banting’s openness to alcohol and tobacco consumption:
“I am certainly more sensitive to cold since I have lost the superabundant fat, but this is remediable by another garment, far more agreeable and satisfactory.” 
“Some have inquired whether smoking was prohibited. It was not.” 
Heck! We’re all humans right? How else would we drain the sorrows of our daily lives?
As a side-note, Banting was in favor of an archaic form of self-quantification (daily weight measurements); at the end of his n=1 he felt regretful not taking before/after selfies:
“I deeply regret not having secured a photographic portrait of my original figure in 1862, to place in juxta position with one of my present form.” 
Joking aside, as of April, 1864:
“It may interest my readers to know that I have now apparently attained the standard natural at my age (10 stone 10, or 150 lbs.), as my weight now varies only to the extent of 1 lb., more or less, in the course of a month.” 
I may be wrong, but a superficial estimation makes me think Banting was calorically restricting in spite of his frequent meals and more-than-moderate alcohol consumption. The nature of his new diet though was more likely to allow for better insulin efficiency compared to his former lower-nutritious diet. He also seems to have been trying to stay away from fats in some foods (pork, oily fish, butter) which makes me more inclined to think that he was indeed calorically restricting.
Anyway, I can hypothesize all day long but I’ll never have a decent certainty about his weight loss journey. Nevertheless, I cannot not be amused by the ‘laid-back’ perspective he had about all of it – booze, frequent indulgences, and ‘philosophy’ of tobacco consumption (reminisce of ‘doctors recommending Camel’ (a cigarette brand).
My bottom line:
Take anything practical from this? Yes, that may be possible.
Be polarizing and use this as a strong argument to support certain dietary beliefs? I would not…
- William Banting (1864) – Letter on Corpulence.
Image: Adapted from Amazon.