As with all components of diet, the amount of fat is strongly rooted in our culture and lifestyle. Chapter 7 begins with a discussion of how, over time, all fat has been labeled as `bad’ based on research showing that dietary fat can increase cholesterol and cancer risk. Dr. Aldana notes that low-fat diets can result in long-term weight loss and reduced cardiovascular disease, but that we need to be more moderate than saying `all fat is bad’.
The graph on page 101 shows that since the 1960s, the percentage of calories from fat has decreased (from 45% to 32% of total calories) while at the same time the percentage of people who are overweight/obese has increased. One cause of this relationship is that we have increased total daily calorie intake (by 335 calories daily in women and 168 in men) without increasing physical activity.
Chapter 7 also takes us through good and bad fats. As a general rule, good fats include polyunsaturated fats (found in plants and fish) and monounsaturated fats (found in the traditional Mediterranean diet). Saturated fats (found in cheese and whole milk) and trans fats (found in margarine and shortening) are considered bad fats. Dr. Aldana does not recommend adding good fats to the diet, but substituting good fats for bad fats. For example, substitute plant oils for high-fat diary products and fatty meats. By substituting 2% of total calories that are from trans fats with good fats, we can reduce our risk of heart attack by up to 50%.
In Chapter 8, we learn about the top layers of the food pyramid – meat, poultry, eggs, dairy, refined starches and alcohol – all of which should be consumed in moderation. Dr. Aldana says the research around meat is quite mixed – some studies show a link between meat consumption and cancer but others refute this claim. He said the best science says that red meat should be eaten sparingly.
The research around dairy products is similarly complex. Overall, low-fat dairy does seem to show better results in terms of cardiovascular disease and stroke, while high-fat dairy does the opposite. Finally, the chapter closes with a discussion of alcohol, reminding us that a small to moderate amount of alcohol (defined as one to two drinks per day) results in a slight decrease in cardiovascular risk. However, the chart on page 131 also shows that with small to moderate alcohol consumption comes a slight increase in risk for cancer.
On Thursday, Dr. Tony will give his perspective on these chapters. And next week we’ll take a look at Chapters 9, 10 and 11. Finally, stay tuned for more information on our Live Chat discussion of this book in early December.
Kerry
