Fat: The excess that plagues us
Fat — both the kind you take in and the kind you put on — has really been taking its lumps of late. There once was a time, after all, when female beauty was characterized as “Rubenesque” — painterly praise for a generous figure — while gentlemen of imposing girth weren’t overweight so much as they were men able to embody the rich measure of their means. Certainly no trust was afforded those who were slim (“Beware yon Cassius. He has a lean and hungry look”); the svelte-set were clearly the sort who cut the fat off steaks and eschewed the most tempting desserts. In the PCE (pre-cholesterol era), that was suspicious behaviour indeed.
We now know, of course, that fat — the dietary kind in foods and the body fats in the blood and adipose tissue — are associated with a long list of health concerns, including heart disease; stroke; breast, ovarian, prostate and colon cancer; and diabetes, to name just a few. Nowadays, Cassius’s lean and hungry look is actually held up as a model (or supermodel) for the rest of us to emulate, not just in fashion (where it’s long and leggy), but in food (light and lean) and even business (lean and mean). At a purely gut level, our preoccupation wh fat in all its forms has led to store shelves laden with low-fat, no-fat, reduced-fat, low-cholesterol, light (and lite) products — all of them aiming to cash in on North American grocery shoppers’ leading nutritional concern.
Given the concern with dietary fats — which are right at the heart of putting on the pounds — one can’t help wondering why it is that one in three Americans (up from one in four in 1980) should be obese (Canadians, as ever, are only slightly behind). Laura Shapiro, writing in the Dec. 4, 1994, issue of Newsweek, speculated that part of the reason stems from people’s confusion about the amount of fat the foods they’re eating contain — coupled with the ever more complicated links new studies are drawing between certain fats and disease. People, Shapiro suggested, “are more confused than ever before about which foods are healthful.”
Joe Schwarcz, Ph.D., and the editors of Foods That Harm, Foods That Heal, note there are “three facts beyond dispute” in any discussion of dietary fats: “One, in small amounts, fats are essential to maintain health; two, the typical North American diet is much too high in fats of all kinds; and three, the fat debate is a gold mine for commercial exploitation of the popular pursuit of low-fat and fat-free alternatives to traditional foods.”
Why do we need lipids, as the family of fats (solid at room temperature), oils (liquid at room temperature) and related substances are known? To begin with, fats add flavour and texture to many foods, and satisfy our hunger long after we’ve completely digested the proteins and carbohydrates in our last meal. Fat’s also the transport vehicle for fat-soluble vitamins A, D, E and K in the body, and provides the body with fatty acids essential to all kinds of body processes, from growth and normal metabolism to the manufacture of sex hormones and cell membranes.
Stored body fat serves a number of other functions. The layer of subcutaneous fat just beneath your skin is an insulator against the cold and a factory for vitamin D production under the sun; other fat deposits cushion and support the vital organs, protecting them from injury. Fat is also nature’s way of preparing you for the next famine, providing a day-and-a-half to two days’ worth of energy for every pound of stored fat.
Since few of us, though, will ever have to make emergency withdrawals from the fat bank, any extra deposits we make now become artery-choking liabilities later. Fat’s different from anything else you ingest. It’s not just because fat is, well, fat, but because of the way our bodies take it in. On a gram-for-gram basis, there are twice the number of calories in fat as in carbohydrates and protein. In itself, that doesn’t explain fat’s precocious ability to turn us into butterballs. The key is that, if you eat a fruit, a vegetable or a slice of bread, your metabolism turns on and breaks it down. Fat’s different: 90 per cent of all the fat we eat gets stored on our bodies. If it goes in, in other words, it goes on.
Thus, the most important aspect of weight control is the amount of fat you eat as you get older; you should try to keep it to 30 per cent or less of your daily food intake, according to Canada’s Food Guide. It’s worth noting that the average North American daily fat intake hovers between 35 and 40 per cent at the moment, which is six to eight times more than anyone actually needs. But even more important than the amount of fat is the kind of fat you ingest — which brings us to cholesterol.
Cholesterol, of course, is the big name in the world of fats, and it’s usually dressed in villainous black. In fact, the body does require some cholesterol — to help in the manufacture of sex hormones, cell membranes and the sheathing on nerve fibres, among other things — but we don’t need it from our diets. The waxy, fatlike compound is produced in ample amounts, thank you, by the liver; the cholesterol we ingest in animal products is superfluous and — depending on your genetic makeup, gender, how much exercise you get and what else you’re eating — potentially fatal.
The problem with dietary cholesterol is that it tends to build up on artery walls, which can lead to atherosclerosis (narrowing of the arteries) and heart disease. Helping cholesterol perform this insidious task are lipoproteins, or lipid-carrying proteins: Low-density lipoproteins (LDLs), known far and wide as “bad” cholesterol, deposit cholesterol on artery walls, while high-density lipoproteins (HDLs) — the “good” cholesterol — scrape cholesterol deposits from blood vessel walls and haul it off to the liver to be processed and eliminated.
As Schwarcz et al point out in Foods That Harm… that’s where the type of fats consumed comes into play: “Highly saturated fats raise blood cholesterol levels because they interfere with the removal of cholesterol from the blood. Monosaturated and polyunsaturated fats, by contrast, either lower blood cholesterol or have no effect on it. When polyunsaturated fats are hydrogenated [that is, hydrogen is added] to make them firm, they become like saturated fats in their effects on blood cholesterol.”
There’s no question most of us could benefit from reducing the amount of saturated fat in our diets, but if you’re concerned about elevated cholesterol levels in your blood, or if you have a family history of heart disease, you should exercise extra caution.
In the meantime, take note: The main sources of saturated fats are animal products, but many of those fats are “hidden” in meat, milk and cheese, says Monica Vegelji, a registered dietician at The Toronto Hospital. “When you’re eating a slice of cheese, it’s difficult to see the fat — it’s not a fat like margarine or butter that you’d spread on a piece of bread that’s easily visible and identifiable, or, for example, the hidden fat in a muffin: It looks like a grain product, but fat has gone into its preparation.”
Whenever possible, check nutrition labels on food products to see whether the fat content’s been broken down as monounsaturated, polyunsaturated and saturated. “Chemically, there’s a difference between poly- and monounsaturated fats, but in terms of the physiological impact they’re both considered to be the better quality of fats,” Vegelji says, “and it’s good to get some source of unsaturated fat in a day. A good source of polyunsaturated fat would be corn oil, sunflower oil or safflower oil. A good source of monounsaturated fats would be olive oil, canola oil or peanut oil.”
Too much of any kind of fat can lead to a high cholesterol level, so the key is achieving a balance, Vegelji reckons. Ideally, for most people, the total amount of fat from all the foods consumed in a day ought to add up to between one and two tablespoons of fat — about two teaspoons per meal over three meals. Keep in mind that a pat of margarine or butter, or a tablespoon of ordinary salad dressing, contains a teaspoon of fat, while just one commercially prepared muffin will have about three teaspoons — or two meals’ worth — of fat. A 50-gram bag of potato chips will be about one tablespoon of oil. So, there’s room for those kinds of things, Vegelji says, “but in small quantities.”
To turn yourself into an effective fat-fighter, check out Canada’s Food Guide, then ask your doctor for a referral to a dietician to make sure you’re optimizing your healthy food choices.