When William Banting could no longer walk upstairs without panting or bend down to tie his shoelaces, he decided that something had to be done. Swimming, walking, Turkish baths and near-starvation diets didn’t do the trick. Desperate, Banting consulted his physician and was advised to give up bread, butter, milk, sugar, beer and potatoes. Amazingly, the pounds began to melt away! The low-carbohydrate diet had worked its magic!
The fascinating part of this account is that Banting, an undertaker by profession, had detailed his story in a pamphlet entitled “Letter on Corpulence Addressed to the Public” in 1863, over a hundred years before Dr. Robert Atkins opened up a can of carbohydrate-free worms with his low-carb, high-fat diet. Banting was ridiculed by the medical establishment because physicians at the time could not stomach the idea of giving up their bread and butter, literally and figuratively, on the say-so of a layman. “Letter on Corpulence” they maintained was unscientific, although they provided no explanation as to why. Atkins was similarly pilloried, but this time the establishment had a rationale. The eggs, meat, and butter in the Atkins diet, they thought, would send cholesterol levels soaring and precipitate a trip to the undertaker.
A rather acrimonious debate followed, with the “establishment” maintaining that the key to weight control was a low-fat diet and Atkins proponents retorting that such diets were doomed to fail. It was the low-carb diet that would trim the waistline! Both sides cherry-picked studies that seemed to prove their point, ignoring any contrary evidence. Many physicians and nutritional scientists grudgingly admitted that indeed there may be more significant weight loss on a low-carb diet, but there was a price to pay, namely sacrificing cardiovascular health. The tit-for-tat continued unabated until a study reported in the Annals of Internal Medicine put some meat into the low-carb argument with a randomized, controlled trial, the gold standard in science.
A total of 148 volunteers were recruited from the general public and divided into two groups. One followed a low-carb diet, the other a low-fat as advised by dietitians through regular meetings. Both groups were given recipes, as well as one meal replacement (shake or bar) a day. They were told to favour mono and polyunsaturated fats over saturated, limit trans fats, and strive for 25 grams of fiber per day. After a year, surveys documented that participants in the low-carb group had maintained a diet with 35% of calories from carbs and 43% from fat, while the low-fat cohort had consumed 52% of calories from carbs and 31% from fat. Total calorie consumption was essentially the same in both groups.
The low-carb group lost an average of 3.5 kg more weight than the low-fat group, but it was the changes in cardiovascular risk factors that surprised many. Total cholesterol, LDL cholesterol, triglycerides, and C-reactive protein (a marker of inflammation), all decreased more on the low-carb than on the low-fat diet, while HDL, the so-called “good cholesterol,” went up. The differences were not large, but the study did demonstrate that a low-carb diet, which by necessity is higher in fat, did not increase the risk factors for cardiovascular disease. Risk factors, though, are not the same as the presence of disease and this study was too short to provide any information about the outcomes of the two diets in terms of actual diagnosis of cardiovascular disease.
These findings are relevant in light of the current popularity of the “Paleolithic Diet,” often dubbed the “Caveman Diet,” which turns out to be a low-carb diet in disguise. Paleo basically eliminates grains and grain products and features copious amounts of meat. It is based on the very dubious idea that human physiology is adapted for ingesting meat, based on our hunter-gatherer ancestors millions of years ago, and not adapted to incorporating grains into our diet. Recent analysis of ancient DNA by researchers at Cornell University has shown that there was indeed an adaptation to a plant based diet after the introduction of agriculture with increased activity of genes that code for the production of important long chain polyunsaturated fatty acids (LCPUFAs). Before the advent of farming, humans had to rely on animal products for these fatty acids that play an important role in health.
Without supporting evidence, Paleo enthusiasts nevertheless maintain that we should be eating like cave dwellers, subsisting on grass-fed meat, poultry, eggs, fish, fruits and non-starchy vegetables, like salad greens, mushrooms and cabbage. This will make us lean like our ancestors, goes the argument, and free of cardiovascular disease, diabetes, cancer, acne and varicose veins, all ailments that Paleo proponents claim did not afflict cavepersons. There is no evidence of the absence of these conditions but there is evidence that life expectancy at the time was only about thirty-five years! And of course, given that the Paleolithic era encompassed some 2.5 million years, there was no one “Paleolithic diet.”
The “modern” Paleolithic diet eschews dairy, thereby curbing calcium intake, and misses out on benefits provided by whole grains and legumes. On the positive side, it does not allow for processed foods, which of course our ancestors would not have had. So, no sugar, no salt, no trans fats, and no refined vegetable oils, which means a more favourable ratio of omega-6 to omega-3 fats. Basically, though, Paleo is a fad diet based on the romanticized idea that hunting and gathering in the Paleolithic age provided a healthier food supply than hunting and gathering in our supermarkets. Of course, what really matters is not whether an argument is plausible, but what the evidence shows.
The studies that have compared a Paleo diet to other regimens have been too small and of too short duration to come to any conclusion. There have, however, been suggestions of improvements in blood pressure, blood sugar, fat around the waist, blood cholesterol and triglycerides, all components of “metabolic syndrome,” a condition that increases the risk of heart disease, stroke and diabetes. There are no compelling studies demonstrating weight loss on a Paleo diet, but no significant health risks have cropped up either. Environmental issues are another matter since raising animals for food is not exactly eco-friendly.
What’s the take-away message here? That low-carb diets rather than being the villains they were once made out to be, may actually be preferable in terms of weight loss and cardiovascular risk factors. William Banting, without realizing it, with his sugar-free, dairy-free diet of beef, fish, poultry and non-starchy vegetables was a Paleolithian. But his doctor did allow something that was definitely not Paleo: claret, gin and whisky. That was all part of “banting,” a term that made it into the public vocabulary in the 1800s to describe low-carb diets. Based on recent evidence, people who would like to shed a few pounds may want to undertake banting.
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