When an individual is aiming to lose weight, the popular wisdom dictates they need to eat less and/or exercise more. Of these two main options, my general belief is that dietary change gets generally more rapid and significant results than exercise in this respect. The evidence suggests that exercise (say walking, running or swimming) is not particularly effective for the purposes of weight loss, and this might have something to do with the fact that the number of calories burned during exercise are generally quite small. Plus, we have the fact that people who tend to exercise more tend to eat more too.
There are, I think, plenty of good reasons to take aerobic exercise, but weight loss does not seem to be one of them. If shedding pounds is the aim, then my advice is a more efficient strategy is to adjust the diet. Generally speaking, I advise here a diet generally low in carbohydrate. Carbohydrate (particularly sugary and starchy ones) tend to cause insulin secretion, which has a key role to play in fat accumulation in the body as explored recently here. Plus, a lower carb diet, particularly if it is rich in protein, tends to satisfy more than a higher carb one, which very often causes individuals to eat less without consciously restricted the amount of food they eat. In other words, this sort of diet can very often lead individuals to lose weight without hunger.
The potential for diet and exercise to promote weight loss popped into my mind when reading about a study which attempted to explore which, if any, of these lifestyle factors is the cause of the rising rates of overweight and obesity in the USA. The study was presented last week at the European Congress on Obesity in Amsterdam, the Netherlands. You can read a report on the study here.
Scientists assessed the metabolic rates of about 1400 adults and about 950 children to calculate the number or calories required each day for stable weight in the adults and normal growth in the children.
They also calculated the likely calorie intake from the 1970s to early 2000s that would account for the rise in overweight and obesity seen over this time. They also estimated the actual calories intakes from data relating to food production and wastage.
Now, with all of this information, the scientists were in a position to ascertain what proportion of the additional calories responsible for increasing weight in Americans appears to have come from increases in food intake. It turns out that in children, the weight changes seen over the 30-year period assessed in the study could be entirely explained by apparent increases in food consumption. In adults, the vast majority of weight increase could be explained in the same way.
Now, this study is quite theoretical and we’re going on reports of the study rather than the study itself. However, if the data stacks up, then this study appears to show that in the USA at least, burgeoning rates of overweight and obesity appear to be the essentially the result of eating more, not exercising less. And this would mean, I think, that in terms of reversing the trend, the emphasis should really be on diet, not exercise.