There's something very wrong with the whole calorie theory of weight loss, especially when it comes to improving our health. People who are overweight-or even obese-are reducing their risk of diabetes and heart disease without shedding even a pound. Instead, they are eating smarter.
Counting calories is our main weapon in the war against flab, and it's the one the overweight are especially exhorted to use if they want to reduce their risk of diabetes and, beyond that, heart disease.
But it's all a dietary blind alley, says leading cardiologist Aseem Malhotra, and one that's being pushed by a food industry that's still loading up its products with processed sugars, while pointing the finger at the high calorie levels in food.
Coca-Cola recently proclaimed that weight loss had everything to do with more exercise, an idea fuelled by the calorie theory of 'energy burn', which has also spawned the high-energy, sugar-laden drinks and foods industry. It's reckoned that sugar is added to more than 80 per cent of fast foods, and one can of cola alone contains nine teaspoons of sugar. Drinking just one can a day will dramatically increase your chances of developing type 2 diabetes, usually a precursor of heart disease, a recent study discovered.
But while we hold to the overly simplistic idea that weight loss is all about burning more energy than we consume, we continue to eat foods that have little or no nutritional value, convinced that calories alone are the measure of health. It's an idea that has also been promoted by the weight-loss industry, which generates around $58 billion in revenues each year in the US alone. Despite these enormous expenditures, the vast majority of their consumers put the weight right back on again-even when they stick to their diets or exercise plans.1
Quality vs quantity
This is another hole in the 'energy burn' theory of calorie-controlled diets. Because the body has a highly sensitive metabolism, any reduction in the amount of food being consumed will cause it to hold on to fat stores and burn less energy in order to survive.
The emphasis is wrong, and it's what you eat-and not just how much-that determines your health. Surveys among the urban poor in sub-Saharan Africa make the point. They revealed an explosion in the rate of people who were obese and overweight; between 1992 and 2005, 35 per cent more people had become seriously overweight or obese. Why? It wasn't because they were eating too much food-such a luxury isn't possible for them-it's because they started to eat cheap, processed foods high in sugar that were becoming more available in their local stores.2
Losing weight is one thing; being well and free of heart disease is another. And eating well-as often typified by the Mediterranean diet, rich in vegetables, fruits, fatty fish, nuts and olive oil-can be better for heart health than drugs like aspirin and statins or surgical interventions such as coronary stents, says Malhotra.3
Fat lot of good
This is true even for people at high risk of developing heart disease. In the Predimed study, which included more than 7,500 Spanish healthy people who were at high risk developing heart disease, eating an "unrestricted" Mediterranean diet-which meant eating as much as they wanted without looking at calories-resulted in a 30 per cent reduction in risk, compared to controls, who reduced dietary fat.4
Interestingly, those who lowered their risk didn't reduce their weight, or total cholesterol, or even their 'bad' LDL cholesterol levels. Instead, the diet reduced levels of inflammation, atherosclerosis (hardening of the arteries) and thrombosis (blood clotting and thickening), and it was achieved in just three months of starting the diet.
Yet, eating the trans fats found in fast and processed food can rapidly increase C-reactive proteins-markers of inflammation in the body-within a few weeks.
Weight loss doesn't seem to be the point unless an individual is seriously obese, which puts an enormous strain on the heart muscle. The Look AHEAD (Action for Health in Diabetes) study discovered that losing weight and adopting a low-calorie diet on its own made no difference to the rates of death from heart disease, fatal heart attack, non-fatal stroke or hospital care for angina in a group of patients with type 2 diabetes, even though they all had followed a calorie-controlled diet for more than 13 years and lost significant amounts of weight.5
Malhotra, a cardiologist at Frimley Health NHS Foundation Trust in the UK and consultant clinical associate to the Academy of Medical Royal Colleges, has catalogued other examples of how losing weight has little to do with improving heart health, but eating better food does:
o Heart-attack patients who started eating fatty fish reduced their risk of a second or fatal attack by 29 per cent, and the benefits were seen within several months, according to researchers of the DART trial, who monitored 2,033 male heart-attack survivors.
o Taking just 1 g/day of omega-3 fatty acids "significantly" reduced the chances of a fatal heart attack in people who'd already survived an attack. In this study of 11,324 heart-attack survivors, the benefits could be seen after just three months of supplementing with fish oils.
o Taking flaxseed oil, also rich in omega-3 fats, achieved a dramatic reduction in blood pressure levels in hypertensive (high blood pressure) patients. Their rate of stroke and heart attack was halved compared with others who were given a placebo, or sugar pill.
With type 2 diabetes costing the UK healthcare system lb20 billion and the US $248 bn every year -figures expected to double over the next 20 years-it's time the food industry was made to pay, says Malhotra. There should be a tax on sugary drinks, while the supply of healthy foods like nuts, vegetables and fruit should be subsidized to encourage their wider availability.
Poor diet alone is responsible for more disease and death than physical inactivity, smoking and alcohol combined, according to the Global Burden of Disease Study.
But don't expect medicine to solve the problem. There's been an exaggerated belief in the benefits of pharmaceuticals, says Malhotra. Drug therapies have been "aggressively reinforced by commercial vested interests, have misled patients and doctors, and promote overtreatment."
The answer is simple. Eat well-and if it's healthy nutritious food, eat as much as you want.
1 Front Biosci [Elite Ed], 2010; 2: 98-104
2 BMC Public Health, 2009; 9: 465
3 Open Heart, 2015; 2: doi: 10.1136/openhrt-2015-000273
4 N Engl J Med, 2013; 368: 1279-90
5 N Engl J Med, 2013; 369: 145-54
From boilers to bodies
A calorie is a measure of energy. In fact, a calorie is the amount of energy required to increase the temperature of one gramme of water by one degree Celsius.
If all that sounds as though it came from the world of boilers and heating systems, well, that's because it did. The idea was first proposed by French physicist and chemist Nicolas Cl'ement-Desormes, whose interest in steam engines led him to devise a more accurate measure of heat energy than horsepower.
He came up with the calorie measure or, more exactly, the kilocalorie (kcal), but he never imagined it would be applied to human biology. He just wanted to know how much energy it took to heat water up to make steam.
The jump to humans was made by an American agricultural chemist, Wilbur O. Atwater. To determine the foods that produced the most energy for America's hard-working poor, he took the kcal and turned it into a food calorie.
To determine the caloric contents of food, he threw various items into a furnace and measured how much heat was produced by each food before turning into ash. This was measured by a device he called a 'bomb calorimeter'. Fats produced twice as much heat, or calories, as did carbohydrates and protein.
Atwater's experiments became medically acceptable after they were applied dietarily by two doctors at the University of Michigan-Louis Newburgh and Phil Marsh-in the 1920s. Thus was born the calorie-controlled diet, based on the idea that, if we consume less energy than we burn, we're sure to lose weight.
Not even wrong
The calorie-controlled diet may not be wrong, but it's so simplistic-and so underplays the complexity of the body, its metabolism and the way it processes different foods-that it might as well be. Essentially it's more to do with the quality of the food you eat than the quantity, as the main story makes clear.
The shortcomings of the calorie-counting dietary approach have been exposed in study after study. In one, the researchers noted that Americans had consumed 4 per cent fewer calories and 11 per cent less fat between 1980 and 1990 compared with the previous decade. Their consumption of fat-free foods increased from 19 per cent to 76 per cent over the same period-and yet, obesity in the US had increased by 31 per cent.
Confused by these findings and reluctant to find fault with the calorie theory, the researchers called the phenomenon "the American paradox".1
The answer to this conundrum may be found in a study from the University of California at San Francisco, which reported that dieting, or calorie restriction, "increases chronic psychological stress and cortisol production-two factors that are known to cause weight gain". Their findings were based on intakes of 1,200 kcal/day.2
1 Am J Med, 1997; 102: 259-64
2 Psychosom Med, 2010; 72: 357-64