Before going any further, it is important to be sure of the meaning of some of the words we have been using: FAT, PROTEIN, CARBOHYDRATE AND CALORIE.
Fat, protein and carbohydrate are names for the main chemical classes of which foods are composed. Just as we visualise something like a garden gate when the question-master in "Twenty Questions" says that an object is vegetable with mineral attachments, so when someone says that a food is fat and protein most of us visualise an egg or a steak and when they say fat and carbohydrate, we think of bread and butter or biscuits or cake.
Since the rise of dietetics as a branch of popular science, many people have learnt enough about the chemical composition of common foods to say roughly how much fat, protein or carbohydrate they contain.
This is essential knowledge for anyone wishing to Eat Fat and Grow Slim, for without it you cannot avoid carbohydrates, nor can you choose the high-fat, high-protein foods.
To help you decide exactly about the composition of any particular food, tables of those with high fat and protein and low carbohydrate are given in Appendix B at the end of the book.
The beauty of this method of slimming is that once you have got the hang of the proportions of fat, protein and carbohydrate in the foods you choose to eat, you can afford to ignore calories altogether. For as Banting so wisely said:
"Quantity of diet may be safely left to the natural appetite. It is quality only which is essential to abate and cure corpulence."
The much publicised diets with emphasis solely on calories are fallacious. It is excess carbohydrates and not calories only that make a fat man fat. The tiresome business of totting up daily calories, on which most modern reducing diets are based, is a waste of time for an obese person. Because, as Professor Kekwick and Dr. Pawan showed, a fat man may maintain his weight on a low-calorie diet, if it is taken mainly as carbohydrate, but he will lose weight on a much higher calorie diet provided he eats it mainly in the form of fat and protein.
"What is a calorie?"
The calorie is the unit of heat. Just as inches are units of length and pounds or grammes are units of weight, calories measure the amount of heat (and therefore energy) a particular food will provide.
All food, of whatever sort, provided it can be digested and absorbed from the gut, can be used to give heat and energy for muscular movement and the various internal processes of the body.
The steam engine analogy holds good this far:
Fuel → Heat → Movement
Theoretically, the amount of heat (number of calories) that can be provided by any particular bit of food is the same whether it is burnt in a steam engine, the human body or a special laboratory oven called a calorimeter. The one exception to this is protein which is not burnt quite as completely in the body as in the calorimeter.
But in obesity, the kind of food more than the amount determines the extent to which it is burnt or stored as fat. The proportion of calories obtained from carbohydrate is more important than the total calorie intake.
Some people cannot get used to the idea of the body burning food to give itself heat and energy. "Where does the burning take place?" they ask.
Well, of course, there are no flames, but obviously since the body maintains a constant temperature even on a cold day, heat must come from somewhere and combustion of a sort does occur in every cell in the body just as it does in a pile of grass mowings left at the end of the garden.
The most astonishing thing about protoplasm, which is the living basis of every cell, plant, animal or human, is the way in which it is able to carry out, without any apparent effort, chemical processes which could not be performed even in the largest and most modern laboratory.
The light flashing at the end of a firefly's tail involves chemical processes more intricate than those going on in the atomic piles at Harwell. Dr. Edward Staunton West, Professor of Biochemistry in the University of Oregon Medical School, Portland, U.S.A., emphasises this point in the introduction to the 2nd (1956) edition of his textbook of Biophysical Chemistry, which deals with the chemistry of human metabolism:
"One of the most marvellous things about protoplasm is the efficiency of its chemical processes and the mildness of the conditions under which they take place. Food materials are synthetised and organised into definite kinds of highly complex protoplasmic structures in an aqueous medium of nearly neutral reaction and at body temperature. Carbohydrates and fats are rapidly and completely oxidised, under the same mild conditions, to carbon dioxide and water with the liberation of as much energy as if they had been burned in oxygen at the temperature of an electric furnace. Here in protoplasm we have chemical reactions proceeding quite differently from those commonly observed by the chemist in his test tube. The main reasons for the difference is that the chemical processes of living things are largely controlled by catalytic systems known as enzymes which are highly specific in their actions."
Nevertheless in spite of the qualitative differences between the chemistry of an engine and of the human body, the same basic reaction takes place whenever or wherever there is combustion with the evolution of heat:
| Basic Equation | ||
|---|---|---|
| CARBON + OXYGEN | = | CARBON DIOXIDE + HEAT |
| Fuel from food or in fat store | + | Air inhaled | = | Air exhaled | + | HEAT via a complex biochemical reaction → energy & movement |
Here the steam engine analogy with the human body should properly end, but most slimming pundits press on and argue that it is your calorie intake, or total consumption of food, alone which determines whether you gain or lose weight. Fat is often severely restricted because it is the most concentrated source of calories.
Mr. Marvin Small, in his popular pocket book, Reduce with the Low Calorie Diet, 1955 edition, with an introduction by Dr. James R. Wilson, secretary to the Council of Foods and Nutrition of the American Medical Association, writes:
"While it is possible to become overweight from over eating almost any food, no matter how few calories it may contain, it is the high calorie foods which are usually the cause of 'men running to belly and women to bum,' as an old English couplet put it. You are on the road to successful dieting when you learn how to satisfy your appetite and appease your hunger with filling low calorie foods, instead of concentrated, high calorie foods.
Why Fat makes Fat
Each gram of fat (about ¼ teaspoonful) contains 9 calories, while each gram of pure protein or carbohydrate contains only 4 calories. An ounce of pure fat contains 255 calories, while an ounce of pure carbohydrate or protein contains less than half—113 calories . . . an astounding difference! So your first lesson is that when you substitute carbohydrate or protein for the fat in your diet, you cut down the calories."
Anyone who has followed the Eat-Fat-Grow-Slim argument so far can see that Mr. Small is over-simplifying the matter. He assumes that the body treats all kinds of fuel alike, as a steam engine does, and that once you have over stepped your calorie ration for the day, the excess is laid down as fat whether the fuel is fat, carbohydrate or protein. To him, fat is the most fattening food because its calorie value is greatest.
We now know that the calorie value of fat is irrelevant as far as slimming is concerned, and that fat is the least fattening of all foods because in the absence of carbohydrate it (and to a lesser extent protein) turns the bellows on the body fires in a fat person and enables him to mobilise his stored fat as well as helping him to burn up the food he eats more efficiently.
Compare what happens when Mr. Fatten-Easily eats fat and protein with what happens when he eats carbohydrate.
On a high-fat diet, water accounts for 30% to 50% of the weight lost. (The other 50% to 70% comes from body fat.)
Turning the bellows on the body fires makes all parts, including its largest organ, the skin, work harder. This gives rise to a considerable increase in the insensible loss of water from the skin surface and to a subjective feeling of warmth. Fat people on high-fat diets often remark on this.
Insensible or "dry" perspiration is water which evaporates from the skin without appearing as beads of sweat. It has no smell.
We all lose water in this way all the time, but when a fat person's metabolism is stimulated by a high-fat diet, this insensible perspiration increases in proportion to the rise in the metabolic rate, and contributes to the weight loss.
To go back to the steam engine for a minute: the orthodox view is that a fat man's engine is stoked by a robot fireman, who swings his shovel at the same pace whether fat, protein or carbohydrate is in the tender. This is true for Mr. Constant-Weight, but as he does not get fat anyway, it is only of academic interest to us. It is certainly not true for Mr. Fatten-Easily, with whom we are concerned. Mr. Constant-Weight has a robot stoker in his engine. The more he eats—of whatever food—the harder his stoker works until any excess is consumed, so he never gets fat.
Recent research has shown that Mr. Fatten-Easily's stoker is profoundly influenced by the kind of fuel he has to shovel.
On fat fuel he shovels fast. On protein slightly less fast but on carbohydrate he becomes tired, scarcely moving his shovel at all.
His fire then burns low and his engine gets fat from its inability to use the carbohydrate which is still being loaded into the tender.
Mr. Fatten-Easily's stoker suffers from an inability to deal with carbohydrate, but he can work fast on fat and protein.
What is it that causes Mr. Fatten-Easily to be affected by carbohydrate in this way while Mr. Constant-Weight can deal with all foods alike and burn up any excess automatically, like the robot stoker?
The answer to this question has only recently been found and it is one of the keys to obesity.
Biochemists and physiologists have discovered that Mr. Fatten-Easily's inability to deal with carbohydrate is due to a block in the chain of chemical reactions leading from glucose to the release of heat and energy in his body.
Glucose is the form in which most carbohydrate is absorbed from the gut. Every bit of starchy or sugary food we eat has to be broken down by our digestive juices to glucose or other simple sugars, before it can be taken out of the gut and into the body for use.
Once through the gut wall, the glucose, in solution, is carried in the blood along veins leading to the liver.
What is not wanted for immediate conversion to heat and energy is stored in the liver as a complex sugar called glycogen and further storage can take place by changing glycogen into fat.
In Mr. Constant-Weight these chemical changes go smoothly and are reversible, i.e. the fat can quickly be broken down again to give energy and, by stepping up his internal combustion, Mr. Constant-Weight soon burns up any excess carbohydrate he has eaten, thus keeping his weight steady.
The chemical reactions which enable the body to deal with food in this way are extraordinarily complicated and we know that they can go wrong. We also know that they depend on certain hormones and enzymes which some people may lack or be unable to manufacture properly.
It is this lack or deficit which is thought to distinguish the Fatten-Easilies from the Constant-Weights, who can deal with an excess of carbohydrate by fanning their metabolic fires until the surplus is consumed.
Mr. Fatten-Easily's trouble is thought to be his inability to oxidise pyruvic acid properly — the so called pyruvic acid block .
He gets stuck with large quantities of pyruvic acid which is bad for him in two ways:
If a fat man stops eating carbohydrate, he makes little pyruvic acid and removes the stimulus to his "fat organ" to make fat. By eating fat and protein he by-passes his metabolic block.
To put it another way: obesity may be regarded as a compensatory overgrowth of the fatty tissues providing for an increased use of fat by a body incapable of using carbohydrate properly.
Feed a fat man fat and protein in place of starch and sugar and he will deal with that quite well, drawing on his stores of body fat in the process. Paradoxically, he will eat fat and grow thinner.
He will also feel well because he will no longer be subjecting his body to starvation and he will be tackling the fundamental cause of his obesity which is not over-eating but a defect in the complex biochemical machinery of his body.