An interesting, and somewhat surprising, finding was uncovered by the National Center for Health Statistics in a recent comprehensive review of the medical literature. After reviewing over 95 medical studies and close to 3 million subjects, the researchers concluded that people medically classified as overweight and low-grade obesity have significantly lower mortality risk than people in the normal weight category! Excess mortality occurs only at the highest levels of obesity, i.e., grade 2 and higher.
These findings are somewhat puzzling, although they are consistent with several previous studies.
A Body Mass Index (BMI) of 18.5 to just below 25 is considered normal weight – e.g., an individual 5′ 8” and 160 lbs. is considered normal weight.People with a BMI of 25 to just below 30 (e.g., 5′ 8” and 190 lbs.) are classified as overweight, while those with a BMI of 30 to just below 35 (e.g., 5′ 8” and 200 lbs.) are labeled grade 1 (or low-grade) obesity. A BMI of 35 to just below 40 is grade 2 obesity.
We don’t know why overweight and slight obesity may be protective.We can only speculate at this point. Among the possible explanations: slightly increased amounts of body fat may provide beneficial and protective metabolic effects.
So, carrying a little extra weight may have some benefits.
Tomatoes are not only tasty, but they may also help prevent strokes.
Tomatoes have high levels of lycopene, which makes them an important source of this antioxidant.
The importance of eating tomatoes, as well as other vegetables and fruits, was underscored by the findings of a Finnish team of researchers in the journal Neurology.
After more than twelve years of follow up, they found that men with the highest levels of lycopene were 55% less likely to have a stroke.
There was no association between stroke and blood levels of other antioxidants – just lycopene.
The length of the study gives it considerable strength, and helps fortify the recommendation that people eat tomatoes, and all fruits and vegetables, regularly, since they are good for one’s health in many other ways.
One word of caution.Your main source of tomatoes shouldn’t be pizza.
A first of its kind study recently evaluated the influence on food choice exerted by a restaurant menu which, next to each food, revealed the amount of exercise needed to burn off the calories contained in that food item.
Interestingly, researchers at Texas Christian University found that the participants in their study, when shown the exercise information, ordered, and ate, significantly fewer calories than those ordering from a menu not displaying either calories or exercise costs.
Most previous studies show that providing information on caloric content alone does not lead to fewer calories ordered or consumed.
The researchers studied a group of 300 men and women, aged 18 to 30 years.
As an example, a female would have to walk briskly for about two hours to burn the calories in a quarter – pound double cheeseburger!
A 154 pound person jogging at a pace of about 12 minutes/mile burns up approximately 295 calories in 30 minutes.
Are we to expect legislation in the future requiring restaurants to list the exercise minutes next to each food item??
Until about four years ago, scientists thought brown fat existed only in infants.Infants cannot shiver, so they use brown fat as a means to keep warm.
Several new studies have shown the existence of brown fat in human adults for the first time – present in the neck, the upper back and elsewhere.
We now have proof that this brown fat actually burns calories at a significant rate – like a furnace.
Brown fat is turned on when people get cold and during exercise.
Scientists are now exploring ways to turn on brown fat without exposing people to cold temperatures or prolonged exercise.
A group of researchers are presently looking at a number of hormones, and other compounds, to determine which are most effective and potent at activating brown fat.Hopefully, they won’t take long.
This week’s BLOG deals with some commonly held weight loss beliefs recently discussed in a NEJM article which are actually unproven PRESUMPTIONS – i.e., widely accepted beliefs that have not been proven true or false in the medical literature.
Among these PRESUMPTIONS are the following:
- Regularly eating breakfast, rather than skipping it, protects against obesity.
Based on two randomized, controlled studies, skipping breakfast did not lead to overeating later in the day, or obesity.
- Early childhood is the period in which we develop exercise and eating habits that influence our weight throughout life.
Although a person’s BMI typically tracks over time, no studies provide convincing evidence for, or against, this PRESUMPTION.
- Eating more fruits and vegetables will result in weight loss or less weight gain, regardless of whether one makes any other changes in diet or behavior.
It is a FACT, however, that consumption of more fruits and vegetables has many other health benefits.
- Yo-yo dieting – i.e., weight cycling – leads to increased mortality.
However, medical research has shown that each time someone regains lost weight it becomes more difficult to lose.It was probably not even necessary to do these studies – just ask any yo-yo dieter.
- Snacking contributes to weight gain and obesity.
Randomized, controlled studies do not support this PRESUMPTION.The key factor in snacking is which food groups are consumed during the snack – veggies and fruits are OK.
There is no scientific evidence to prove,or disprove,any of the above beliefs.
We now conclude our exploration of commonly held weight loss beliefs.
PART 2: The FACTS
A recent New England Journal of Medicine article http://www.nejm.org/doi/full/10.1056/NEJMsa1208051 explored commonly held weight loss beliefs, separating them into FACTS,MYTHS and unproven PRESUMPTIONS.
This week’s BLOG is devoted to the FACTS – i.e., the things we do know with reasonable confidence that are supported by good scientific evidence.
Included among the FACTS are the following:
- Obesity is best treated as a chronic condition – like hypertension or hyperlipidemia- requiring on-going management to maintain long-term weight loss.
Meal replacements, and/or diet prescription medications, with behavioral modification, exercise and diet counseling under medical supervision provide an ideal forum to attain the goal of long term weight loss.
- Some prescription drugs can help achieve meaningful weight loss and maintain the weight reduction as long as they continue to be used.
Fortunately, there are new prescription diet medications approved by the FDA which have increased the options available.
- Better weight loss is achieved with meal-replacement products according to medical literature.
Providing diet foods containing protein derived from egg white, milk and other hi-quality proteins that are low in calories (and tasty) is essential in attaining this goal.
- Although heredity plays an important role it is not destiny!
Moderate environmental changes, diet foods and prescription medications can still promote weight loss in spite of genetics and metabolism.
- Regular exercise has been shown to help achieve long-term weight maintenance.
Physical activity is vital, but it must be vigorous, aerobic and consistent (5-7 days/week) to help attain long term weight maintenance.
- Increased levels of exercise increase health, even without weight loss and regardless of body weight.
Medical studies have repeatedly demonstrated that regular aerobic exercise improves health, and reduces risk factors, in many other ways.
Our next BLOG will probe the commonly held beliefs which are unproven PRESUMPTIONS.
PART 1: The MYTHS
This week’s BLOG is devoted to some commonly held weight loss beliefs which are actually MYTHS – i.e., scientifically incorrect, & false – as identified in a recent NEJM publication.
Included among the MYTHS are:
- “Small but regular increases in physical activity will produce large long term weight loss” For example, it has been claimed that walking 1 mile per day will result in a weight loss of >50 lb over a 5 year period. In truth, the total weight loss will only be about 10 lb based on recent studies using computational models to determine energy expenditure and predict weight change in humans.
- “Losing weight too fast results in less weight loss in the long term” In fact, in several weight loss trials, more rapid and greater initial weight loss has been associated with lower body weight at the end of long term follow-up.
- “Breast feeding is protective against future obesity in the child” Actually, the existing scientific data indicate breast-feeding does not have an effect on future obesity, although it does have other important benefits for both infant and mother and should therefore be encouraged.
- “Sexual intercourse burns 100-300 kcal for each participant” The truth is, a man in his early to mid 30’s expands about 21 kcal during sexual intercourse – far less than is commonly claimed.
Our next BLOG will deal with the commonly held beliefs which are true FACTS.