If you want to lose weight and keep it off, look to real science, not empty promises.
One of the things that makes my job interesting is helping people sort out fact from fiction when it comes to dieting and sound nutrition. You don’t need to look further than a newspaper, magazine, or infomercial to find an outrageous amount of nutrition fiction. What’s a little harder is to understand is where there is actual science (and good science) behind diet and health advice.
So it was with great delight that I read an interview in the NY Times earlier this week with Dr. Jules Hirsch. Dr. Hirsch has been researching obesity for nearly 60 years and is emeritus professor and emeritus physician in chief at Rockefeller University.
The interview focused on the recent stir caused by a study published last month in The Journal of the American Medical Association. In it researchers suggest that after losing weight people on a high-fat, high-protein diet burned more calories than those eating more carbs.
This study is a great example of how a piece of research can get misinterpreted by the media and leave people with the wrong idea about how to implement the findings in real life. In this case, they might be led to believe that a high-fat, high protein diet is the way to a svelte form.
In his NY TImes interview, Dr. Hirsch helped to clarify how this is not necessarily the right conclusion from this particular JAMA Study. He states, “Such low-carbohydrate diets usually give a more rapid initial weight loss than diets with the same amount of calories but with more carbohydrates. But when carbohydrate levels are low in a diet and fat content is high, people lose water. That can confuse attempts to measure energy output. The usual measurement is calories per unit of lean body mass — the part of the body that is not made up of fat. When water is lost, lean body mass goes down, and so calories per unit of lean body mass go up. It’s just arithmetic. There is no hocus-pocus, no advantage to the dieters. Only water, no fat, has been lost.”
Perhaps the most important illusion is the belief that a calorie is not a calorie but depends on how much carbohydrates a person eats. There is an inflexible law of physics — energy taken in must exactly equal the number of calories leaving the system when fat storage is unchanged. Calories leave the system when food is used to fuel the body. To lower fat content — reduce obesity — one must reduce calories taken in, or increase the output by increasing activity, or both. This is true whether calories come from pumpkins or peanuts or pâté de foie gras
Dr. Jules Hirsch
It should be noted that, in addition to looking at total calories, the type of food you eat does matter. First, nutritional composition counts toward good health – so make sure what you’re eating is loaded with vitamins, minerals, and fiber. Second, we do know from other research (like the work of Dr. Barbara Rolls on volumetrics) that some foods that are high in water content – like fruits, veggies, and broth based soups – can help you fill up on fewer calories. Same for protein-based foods – they have been found to help keep you full. And keeping full on fewer calories is key to weight loss. So the type of food matters, but next time you see a lose-weight-quick ad, heed Dr. Hirsh’s words. When asked what he would tell someone who wanted to lose weight he replied: “I would have them eat a lower-calorie diet. They should eat whatever they normally eat, but eat less. You must carefully measure this. Eat as little as you can get away with, and try to exercise more.”
Not magic, but sound advice.