In her published articles, numerous interviews and a groundbreaking book “The Obesity Epidemic” (among several other well-received titles), British researcher and nutritionist Zoe Harcombe has crafted a bold and compelling explanation of how millions of people across the developed world have become obese in just the last generation or two.

It’s a serious problem. Consider these facts:

  • Fully two-thirds of the populations of the UK, the USA and other western countries are overweight.
  • Our collective activity levels haven’t changed appreciably in decades, even as we pile on the weight.
  • Our intake of dietary fat and saturated fat has declined measurably, even as we all seem to be getting fatter and fatter.

To these set of facts, Harcombe posits the key question: “Why?”

Interview: British expert on causes of obesityWhy have millions of people become dangerously obese? Why can’t a strategy of “eat less/exercise more” counteract our growing collective girth? Why isn’t the obsession with low-fat and fat-free foods keeping us slim and trim? And why are kids and teens suddenly battling weight problems, even as we revamp school lunches, badger parents to restrict their children’s screen time and invest enormous resources in getting kids to be active with sports and recreation?

In this exclusive interview with Vance Online Networks Contributing Editor Dan Murphy, Harcombe explains how—and why—the Western world got to be so overweight.

Q). You noted that “official dietary recommendations” from government and medical authorities changed dramatically in the late 1970s and early 1980s, with an emphasis on eating less red meat and substituting “starchy foods”—though in fairness, the goal was to choose whole grains, fruits and vegetables—to replace all that saturated fat in meat. How did that happen?

Harcombe: It emanated from a single study by American physician Ancel Keys: The Seven Countries Study—Finland, Greece, Italy, Japan, The Netherlands, United States and the former Yugoslavia—which was published in Circulation in 1970. In that report, Keys observed a relationship between saturated fat in the diet, cholesterol levels and coronary heart disease, and he concluded that diets high in saturated fat caused heart disease via cholesterol.

In 1977, Sen. George S. McGovern, then-chairman of the Senate Nutrition Committee, was introducing new dietary recommendations. At that time, the Seven Countries Study offered the most comprehensive data available. Although there were dissenting voices at the time, they didn’t have a 14-year study to offer counter-evidence. Opponents of McGovern’s plan could have torn apart the Seven Countries Study, but either they didn’t or they did and were ignored, and McGovern announced new “Dietary Goals for the United States” and the rest, as they say, is history.

Q). Since Keys’ Seven Countries Study apparently persuaded a lot of nutritional experts, what was wrong with his research?

Harcombe: A lot. Keys’ entire thesis was founded on an incorrect assumption.

First of all, cholesterol does not cause heart disease. Cholesterol, along with protein, phospholipids and triglycerides—the four substances found in all lipoproteins—are present in damaged arteries, but the lipoproteins are there to repair that damage. Cholesterol does not cause arterial damage, any more than police cause crime, even though they’re always right there at the scene.

Since dietary cholesterol is “not guilty,” there’s no logic for going after dietary fat. The only foods that contain cholesterol are animal foods, such as meat, fish, eggs and dairy, and they all contain dietary fat. To increase cholesterol during his experiments, Keys had to feed people animal foods. That’s the only way he could increase the intake of dietary cholesterol. He then concluded that this dietary change had no impact on blood cholesterol levels. Therefore, he exonerated animal foods back in the 1950s! I’m not aware of anyone else who has spotted this fundamental error in logic: Cholesterol—and thus dietary fat—doesn’t cause heart disease.

Q). What else was wrong with this study?

Harcombe: The fact that Keys didn’t know fats from carbs. In his study, cake and ice cream were counted as saturated fat, even though they’re predominantly carbohydrates. Keys also assumed that meat and eggs are full of saturated fat—as do many dieticians even today. But meat and eggs contain more unsaturated than saturated fat. Even lard has more unsaturated than saturated fat. Nutritional ignorance is at the heart of most of our current and badly flawed dietary advice.

The bottom line is that the Seven Countries Study data do not support Keys’ conclusions that cholesterol and dietary fat cause heart disease. It’s refined carbohydrates that are the problem, since eating them triggers an insulin response in the body that leads directly to enhanced storage of those calories as bodily fat.

Now, it’s unrealistic to expect people to grasp the complexities of carbohydrate metabolism, the role of insulin in fat storage and utilization, or even the notion that dietary protein and fat are handled differently than carbs in human digestion. But the “solution” to the obesity epidemic has been distilled down to a mantra of “Do More/Eat Less.” Cut down on the calories consumed and increase calories burned with exercise. That’s about as simplistic as it gets.

Q). But the concept of “eat less and exercise more” seems logical—you take in fewer calories, you burn up additional calories and you lose weight, right? Yet you’re suggesting it doesn’t work?

Harcombe: The simplicity of “eat less/do more” makes this platitude compelling, but look at the evidence: If it were working, why has obesity skyrocketed? The ultimate naiveté in weight loss is thinking that the body magically gives up fat when faced with a calorie deficit, because you ate less and exercised more. That’s not correct.

When you eat less, the body tries to get you to eat more. It sends out messages: A rumbly tummy, food cravings, light headedness, inability to concentrate, irritability. You respond to these signals, and sooner or later, you give in and eat. Then you feel better—those nasty hunger symptoms disappear—and you learn to respond to attempts to eat less by eating more. At the same time as it’s trying to get you to eat more, the body tries to get you to do less when you’re eating less. You can’t be bothered to go out with friends, let alone go to the gym. You become lethargic and tired. Less energy in means less energy out, not more weight lost.

The same thing happens if you try to exercise more: The body tries to get you to eat more to provide the additional fuel you need. That’s just the physiological response to trying to eat less and do more.

Q). So you’re suggesting that reducing calories consumed and increasing calories used up in exercise doesn’t work?

Harcombe: Yes, and here’s the problem: People trying to eat less eat the wrong things—they shun fat and choose carbs instead. Yet fat is the most versatile macronutrient. It can be used for energy, and it can be used for metabolic repair. Carbs can only be used for energy.

In fact, for a moderately active person, 75% of one’s daily energy requirement is for repairing cells, building bone density and fighting infection—ie, running the body. The body needs fat and protein to do this. Only 25% of daily calorie needs are for energy production, and our energy needs can be fueled by carbs, or fat or a mixture of both.

But since McGovern, the official dietary advice is to consume at least 55% of daily caloric intake as carbohydrates. Unless you’re Michael Phelps, you just don’t need that much.

Tomorrow—Part II of the interview: What we can do to solve the obesity problem (Hint: It involves livestock producers).

The opinions expressed in this commentary are solely those of Dan Murphy, a veteran food-industry journalist and commentator.