Dangers of the ‘Low-fat’ Dogma

According to the World Health Organisation (WHO), obesity worldwide has more than doubled since 1980. In 2014, over 1.9 billion adults (18 years and older) were overweight – 600 million of them were obese.

That means 39% of adults aged 18 years and over were overweight in 2014, and 13% were obese. Furthermore, 42 million children under the age of 5 were overweight or obese in 2013.

Those figures and statistics are extremely worrisome. They take the obesity issue to a whole new level: obesity is an epidemic. As such, it should be considered a global emergency for many reasons, including:

1. Most of the world’s population lives in countries where being overweight or obese is a substantial killer.

2. The cost of these illnesses will be “astronomical”, as stated by Marion Nestle, who chairs the Department of Nutrition and Food Studies at New York University.

But, as is elegantly put in the summary of the fact sheet on the WHO website, ‘obesity is preventable’. The WHO goes on to explain the fundamental cause of obesity. Far from being unexpected, the assumption is that there is an energy imbalance between calories consumed and calories expended. Globally, there has been:

• an increased intake of energy-dense foods that are high in fat; and
• an increase in physical inactivity due to the increasingly sedentary nature of many forms of work, changing modes of transportation and increasing urbanisation.

Unfortunately, the answer to this global public health issue is not even close to helping patients. The WHO’s answer as to what causes the obesity epidemic is part of the reason why we inefficiently try to deal with it.

To me, it is very clear by now that the energy imbalance between calories consumed and calories expended is to blame. However, the concept of calories is most likely wrong and cannot explain obesity alone.

The problem in obesity is not excess weight, the problem with obesity is that the brain is not seeing the excess weight.Prof Dr Robert H Lustig Paediatric Endocrinologist

In this, the work of Dr Robert H Lustig (Professor of Paediatrics in the Division of Endocrinology; and Director of the Weight Assessment for Teen and Child Health Programme at University of California, San Francisco) is more than noteworthy.

But more importantly, WHO’s answer pointing towards fat as the main issue (‘increased intake of energy-dense foods that are high in fat’) needs to be reassessed. Evidence clearly shows that such foods are not solely responsible for the obesity epidemic. Fat alone cannot explain obesity.

Prevalence of diabetes

According to the WHO, the number of people with diabetes has risen from 108 million in 1980 to 422 million in 2014. The global prevalence among adults over 18 years of age rose from 4.7% in 1980 to 8.5% in 2014 and has been rising more rapidly in middle- and low-income countries.

Diabetes is a major cause of heart attacks, stroke, blindness, kidney failure and lower limb amputation. One death every six seconds can be attributed to Type 2 diabetes.

Worldwide, approximately 1 in 10 adults has Type 2 diabetes mellitus. A significant fraction of the population has some degree of insulin resistance – approximately 40% in the US. The projection the WHO makes is that diabetes will be the seventh leading cause of death in 2030.

The incidence of diabetes is expanding extremely quickly and is a legitimate cause of worry. This is particularly because – as the WHO fact sheet reminds us – diabetes can be prevented or delayed with a healthy diet, regular physical activity, maintaining a normal body weight and avoiding tobacco use.

The WHO is actively promoting diabetes prevention and care management. There even is a World Diabetes Day. However, as surprising as it may seem, sugar is still not a definite target in the fight against diabetes.

With preventable diseases, patients can actually be part of the prevention behaviour. That is one of the most interesting aspects of nutrition as a field of study. Patients are in control of what food they purchase and consume. Provided they understand the consequences of their choices, they can be responsible. They need to understand the impact that the food they eat has on their health.

Sugar – a cheap replacement

In previous papers and articles, we have shown that scientific evidence does not support the theory that was seen as the truth for so long. For ages, fat has been considered the cause of metabolic disease – but it obviously is not.

The fact that we have believed it for so long has led to room for concepts like that of Ancel Keys to grow and prosper. This destroyed perfectly good food habits that we used to have, leading to what we might now call the worst food epidemic ever known.

Those beliefs have driven us to take fat off our plates over time. That in itself is not the issue (although the body needs fat to work properly). But since fat and flavours are very closely related, fat-free or low-fat products were literally not edible. Neither were they satiable.

With close to no fat in our food, we had to find a solution; something to replace it in order to make food products palatable. And if that solution could be affordable, then the food industry would thrive.

Sugar is cheap. Sugar tastes good. Sugar sells. So companies will have little incentive to change.Prof Dr Robert H Lustig Paediatric Endocrinologist

Sugar was the answer everyone was looking for at the time. It replaced fat, made the food taste good and was inexpensive. It may even have been the easiest and cheapest solution at the time.

More importantly, it generated that strong positive reward in your brain – such a reaction in fact, that one can be addicted to sugar and crave it more and more.

Erroneous assumption about fats

Contrary to popular belief, fat does not make you fat; sugar does. The more sugar we ingest, the fatter we become. We then look for dietary solutions and end up consuming more low-fat, diet-food products.

This adds to the problem by providing fewer fats and even more sugar to the body. All the sugar consumed stresses the pancreas; this, in turn, has an effect on insulin resistance.

The assumption that fat is unhealthy is therefore erroneous, as is the assumption that we consume too much of it. As a case in point, palm oil is a healthy source of lipids and vitamins, and is also free of trans fats. Yet, it has suffered a smear campaign over the last few years. As with many ‘low-fat’ products, we have found ‘palm oil-free’ products on shelves.

Fat in general, and palm oil in particular, is not – and never was – the culprit it was made out to be. Palm oil has a balanced composition that makes it one of the healthier options among oils and fats. Studies published over the last 10 years show precisely that we should not worry about palm oil, as it can be part of a balanced diet.

Sugar is not as easy to defend. Fructose – one of the dozens of forms of sugar – has always been present in fruit; but other kinds of sugar added to just about every food product have no particular metabolic benefit.

Over-consumed, sugar does more harm than good. It promotes obesity and is responsible for diabetes, two epidemics that are among the leading causes of mortality.

Guiding consumer choices

Let me be straightforward: you should cut added sugars in order to reduce the amount consumed. But sugar is often hidden in food products; and since it has so many different names, it is difficult to identify. Low-fat products in particular, are riddled with hidden sugars.

We should move away from the low-fat dogma, and governments and regulators should absolutely support that shift. We should be looking to restore food habits we once had, where fat was considered healthy and sugar was not so frequently found in food. Those in charge of publishing dietary guidelines should recognise the scientific evidence supporting fat over sugar and take immediate action.

A healthy balance of fats should always be a key component of the diet. Palm oil is a prime example of this – it is good and healthy; and its balanced composition of saturated and unsaturated fat makes it also ideal for cooking.

Furthermore, it is very difficult to over-consume fat, as it is very satiating. Consuming fat in a low-carbohydrate diet also makes it easier for the body to access fat for energy.

Consumers are able to decide what they eat. However, they should be guided by the best available science. Moving away from added sugars and other carbohydrates, while adding more natural fats like palm oil, will rapidly improve health. It is time that regulators recognise, and endorse, this fact.

Dr Guy­André Pelouze
Cardio-thoracic Surgeon, France