Weight Loss, Dieting & Obesity

Should I Adopt a Low Fat Diet? Part One.

Low fat diets, low fat recipe books and manufactured low fat foods are everywhere these days. Yet probably nothing in the area of nutrition, diets and weight loss has been so misunderstood as dietary fats.

Common misunderstandings about dietary fats / oils

The confusion is understandable. More is known today about different types of fats than was the case even a decade ago. The ideas about fats that were accepted by the experts twenty or thirty years ago are now largely recognized to be seriously erroneous, yet it takes many years - maybe even a generation or two - before new scientific knowledge becomes common knowledge.

This confusion is readily exploited by various players in the manufactured foods industry. "Low Fat" products are well labelled and easily found - but misunderstood by most consumers. Consumers expect that "low fat" somehow also means "low calorie". The manufacturers exploit that assumption mercilessly. Advice I give for all processed and packed foods is to always read the label. You will quickly discover that "low fat" almost always means increased refined flours and sugars. It does not at all mean "low calorie".

Processed foods aside, there are widespread misunderstandings about the word "fat", which can mean different things in different contexts.

Some "diet gurus" in times past have made such outlandish, foolish and just plain false claims that humans "can't get fat if they don't eat fat."

Are Bananas Fattening? Recently I read a comment from a dietician (who should know better) supposedly debunking a diet 'myth' that bananas are fattening. She replied that this was wrong because bananas contain very little fat at all.

A food does not need to contain fat to be fattening. Those two different uses of the word "fat" in the same sentence have confused even that qualified dietician. Would she tell us that we can eat a bucket full of sugar because it contains no fat and therefore "isn't fattening"? I surely hope not.

In other words, of course bananas are fattening if eaten to excess - just like any other food.

To be "fattening" a food only needs to contain calories and be eaten above your energy requirements. It matters not whether those calories come from carbohydrates, fats or proteins as to whether a particular food is fattening.

Even the above statement has its exceptions. Some foods produce hormonal effects that may raise insulin levels and encourage the conversion of glucose and store it as body fat. The biggest offenders that do this are sugars and starches - not fats.

Some foods have the opposite effect and actually stimulate metabolic function and can assist in weight loss. Interestingly, several of the known foods that can do this are certain specific types of fats. (Omega 3 and Conjugated Linoleic Acid are two examples published in major peer reviewed medical journals in recent times.)

The knowledge of these things was not available to the public and not even discovered by the sciences until recent years. Accordingly, older beliefs persist, although proven false.

Another piece of dietary theory from the 1960's and '70's, now clearly shown to be misguided, is that because fats contain nine calories per gram and carbohydrates contain four calories per gram, we will lose weight by replacing fats with carbohydrates. It sounds good, until examined closely.

That theory fails on several counts.

1. First of all, proteins are also four calories per gram - the same as carbohydrates. Ask yourself who was behind the mass marketing and lobbying to increase low nutrient carbohydrates such as grains instead of the equal-calorie yet more nutrient rich proteins in your diet - and why.
2. Secondly, next time you mound your plate with mashed potatoes or rice, look at it first. Look at the size (then mentally discount the water content of it). Did you EVER really have about half the quantity of pure fat on your plate? Of course not. It is far, far easier to raise your carbohydrate intake than to reduce your fat intake. By following the advice to reduce fats and raise carbohydrates, you are simply increasing your total caloric intake. Obviously, that is counter-productive. Actually, it is even worse than that. Fats/oils are very light in weight. They float on water. Carbohydrates are denser, heavier. For an equal volume, such as a level teaspoon, fats and carbohydrates have approximately equal calories. Now, take another look at that pile of mashed potato or rice on your plate.
3. Thirdly, this theory completely ignores nutrition. It concentrates on calories as if they are the only factor that is important in your diet. Always remember that sugars, grains and other starchy foods are low in nutrients such as vitamins and minerals (compared to complex fruits and vegetables, which are to be encouraged). Your body has absolutely no essential requirement for pure carbohydrates, but you cannot live without proper fat intake. Fats are essential for many metabolic processes - not merely an energy source.
4. Fourthly, if consuming processed goods for your carbohydrate source (breads, french fries, pastries, etc.), take a close look at the list of ingredients. Almost always, they still contain fats or oils anyway - not to mention sugars, salts, chemical preservatives, and other undesirables.

Another of the older beliefs now disproved is that "animal fats are bad but vegetable fats (oils) are good". Similarly, that "saturated fats are bad and unsaturated fats are good."

More modern research, however, proves that there are good animal and other saturated fats, and there are bad animal and other saturated fats in terms of human nutrition and health.

Likewise, there are both good and bad vegetable and other unsaturated fats (oils).

The falsehood that animal fats or saturated fats are always bad is very readily disproved. Human body fat itself is saturated fat. Even a healthy, normal weight person will be roughly 20% body fat. The body manufactures it from dietary fats, proteins and carbohydrates. Without saturated body fat, you would die.

Another clear indication that saturated fats are essential to human health and nutrition is that human breast milk contains a high level of saturated fat (as well as unsaturated fats). No-one questions the nutritional importance of breast milk, do they?

Probably the most serious of the older beliefs now proven false is that low fat diets make you lose weight. While this can be demonstrated as true in the short term, it is now well known that it does not hold true longer term. Almost every study on this matter shows that people on low fat diets lose weight initially, though eventually regain even more weight than they had before they began the diet. The human body, if deprived of fats, will go into "starvation mode", slow the metabolic rate and encourage the conversion of glucose into fat and deposit it into adipose (fat) cells.

Low fat diets don't work for permanent weight loss.