I have just discovered a report entitled “Obesity in Canada: A Whole-of-Society Approach for a Healthier Canada” (1), which I find very encouraging. It has been produced by a Standing Committee of the Senate and demonstrates a willingness by politicians to examine the scientific evidence in a genuinely objective manner.
Here are some of the key points:
- There has been at least a twofold increase in the proportion of obese adults and three-fold increase in the proportion of obese children since 1980.
- Over the same period, there has also been an increase in the rate of type 2 diabetes (T2D), heart disease, stroke and some cancers, and therefore an increased demand on the health care system. This results in a lower rate of employment as well as a higher absenteeism rate and decreased on-the-job productivity.
- In the early 1970s Canadians were encouraged to reduce fat consumption. As a result there was a reduction in the consumption of fat from about 40% E to 31% E by 2004. As the incidence of obesity increase markedly over this period, this effectively rules out fat as the primary factor responsible.
- Although there are no data available for Canada, the consumption of refined carbohydrates steadily increased between 1980 and 2000 in the United States. It is highly likely that a similar trend would be expected in Canada.
- The Committee was told by a number of witnesses that there is little or no evidence that fat, in particular saturated fat (SFA), should be limited in the diet. This advice is rooted in studies from the 1950s and 1960s that have since been reviewed and been found to have been poorly designed, misinterpreted or over-interpreted. It was suggested that the reduction in fat has replaced by an increased consumption of carbohydrates, particularly in the form of processed foods.
- While the intake of sucrose (sugar) has fallen, this has been more than compensated for by an increase in High Fructose Corn Syrup (HFCS) which is effectively the same as it is broken down to glucose and fructose.
The roles of glucose and fructose explained
It is fascinating to note the insight into the role of sugar in the body. Here are some quotes from the report:
- “After the sugar has entered the small intestine, where sucrose is broken down to its constituent glucose and fructose molecules, it is absorbed into the blood stream and transported to the liver. While glucose proceeds from the liver through the blood stream without further processing to the rest of the body, fructose must be broken down further within the liver where it processes some of the fructose to glucose…”
- “If the liver becomes overwhelmed with fructose, fat production goes up. As such, the committee was told that increased consumption of fructose, as a component of sucrose and HFCS, results in overproduction of fat in the liver, leading to increased visceral fat, which is fat in and around the abdominal organs.”
- “Once sugar and starch have been processed into glucose the increased concentration in the blood stream stimulates the secretion of insulin from the pancreas. Insulin acts on cells throughout the body to take up glucose from the blood to supply their energy. However, insulin also promotes the synthesis of fatty tissue and inhibits the breakdown of body fat as a source of energy.”
- “Witnesses spoke of the increasing diagnoses of metabolic syndrome. As described above, the consumption of carbohydrates results in the secretion of insulin which facilitates the uptake of glucose into cells throughout the body. The consumption of refined carbohydrates and free sugars cause larger surges in insulin secretion into the blood than does the consumption of food in its natural state. Prolonged exposure to insulin results in Type 2 diabetes when cells become less sensitive to insulin, known as insulin resistance, prompting even more insulin secretion in order to get cells to respond. Eventually the pancreas’ ability to produce insulin may be lost altogether.”
- “Metabolic syndrome, or metabolic disorder, caused by insulin resistance, precedes the development of Type 2 diabetes. Metabolic syndrome includes high blood pressure, high blood glucose levels, excess body fat, primarily visceral fat, and abnormal cholesterol levels. If diagnosed early enough, the condition can be reversed through diet and physical activity. If left untreated, the condition can progress to the chronic diseases described above, namely Type 2 diabetes, heart disease, stroke and some cancers. Type 2 diabetes can include such complications as kidney failure, blindness, dementia, and amputation due to the loss of feeling in the extremities leading to increased risk of infected wounds.”
- “While these conditions are commonly associated with excess weight, members heard that there has been an increasing incidence of them among normal weight individuals. The committee was told that although 80% of the obese population is metabolically ill, the proportion is also quite high among normal weight adults at 40%. Members were told that although life expectancy has been increasing over the past several years, so too have the number of years spent in ill health at the end of life. Several witnesses testified that the primary cause of metabolic syndrome is sugar as well as refined carbohydrates.”
The comments on fat are just as perceptive:
- “For the past twenty five years, Health Canada has advised a low fat diet. It has also advised that dietary fat be primarily the unsaturated fats and oils from vegetables and fish and that consumption of saturated animal fats found in meats and dairy be minimized.”
- “Members were told that while saturated fats have been part of our diet for thousands of years, vegetable oils are a recent addition in the past few decades. It was pointed out that saturated fats are chemically stable during cooking and that recent reviews of the scientific evidence suggesting that these fats are unhealthy are indicating there has been a misinterpretation of the data.”
- Further, the committee was told that the unsaturated vegetable oils are unstable when cooked, producing oxidation products whose safety profile have not been properly assessed. As a result, it was suggested that the effect of reducing dietary saturated fat and increasing unsaturated fat may be introducing a new health consequence that has not be properly explored as yet. Several witnesses also pointed out that the effect of dietary advice to reduce overall fat consumption was to increase consumption of carbohydrates, primarily as processed foods, which can produce metabolic syndrome.”
The above extracts demonstrate that the committee really has tried to get to grips with what is happening in the body. I find it especially commendable that there is no mention of the lipid hypothesis dominates these deliberations in so many countries. There has been a genuine attempt to focus on what is happening in the real world and try to find a rational explanation to explain it. This is in stark contrast to the UK, where the Scientific Advisory Committee on Nutrition (SACN) report on carbohydrates (2) made no attempt to provide any valid explanation for the increased incidence of obesity and the related chronic diseases. It is significant that the committee was able to adopt a critical approach to the official government line and recommended that the Minister of Health undertakes:
“a complete revision of Canada’s food guide in order that it better reflect the current state of scientific evidence. The revised food guide must:
- Be evidence-based.
- Apply meal-based rather than nutrient-based principles.
- Effectively and prominently describe the benefits of fresh, whole foods compared to refined grains, ready-to-eat meals and processed foods.
- Make strong statements about restricting consumption of highly processed foods.”
The politicians who worked on this report have done an excellent job and it is to be hoped that the government will respond positively and constructively. It is especially noteworthy that the powerful vested interests have been shrugged off and that there have been researchers/academics prepared to challenge the dogmas that have got us this mess in the first place. I hope that politicians in other countries will follow the lead given by the Canadians.