Wednesday, February 15, 2012
I am almost done reading the book by Gary Taubes "Why we get fat and what to do about it" which is a simplified version of his much more comprehensive book "Good Calories, Bad Calories". Gary Taubes talks about the connection between overeating and weight gain in a different way than what most of us are used to hearing: Prompted by hormones, primarily insulin, our body will store calories we eat, regardless of whether they are carbs or fat, in the fat cells in our body. Insulin can cause this to happen regardless of whether we need these calories for energy at the moment or not. According to Taubes this means that if our insulin levels are high enough and our body needs to use energy we will get hungry because all the available calories are put away in the fat cells where they are unavailable for use. Therefore obesity is the cause of overeating, not overeating the cause of obesity.
Taubes makes the comparison of a young person growing. To say that a child is growing because they are overeating is obviously ridiculous. We assume that growth and physical changes during adolescence are the result of hormonal changes and that teenagers eat a lot BECAUSE they are growing.
Increasing insulin levels are caused by consuming carbohydrates and those carbs with the highest glycemic index are considered the worst. There are other reasons given for why some people seem to store a lot of calories they eat in fat tissue while other people seem to deposit them in muscle tissue where they are used for energy. Genetics play a role here.
When I look at my dogs I know that this is true. My whippets were bred for racing and they have probably no more than 3 percent body fat. People who don't know and understand the breed will occasionally ask questions about how often and how much I feed them and are suprised to hear that these dogs eat huge amounts and get one of the most expensive dog foods on the market.
My Beagle Honey is on the other end of the spectrum. When she came to us she weighed 47 lbs. at 2 years of age. I know that she was part of a research colony for a nutritional study but I don't know what her diet consisted of before we got her. I put her on a low-fat, high-fiber diet and fed her small portions, 1/4 cup of food twice a day. This was 8 years ago and I had never questioned the wisdom of cutting fat and calories and increasing fiber and activity for weight loss. In this case my approach worked. Honey lost 20 lbs. in 3 months, rivaling "Biggest Loser" results. She is now on 1 cup of high-quality food a day, about 30% carbs, 40%fat and 30%protein. Not ideal for a dog but she maintains her weight with the help of portion-control and regular exercise. Beagles commonly have hypothyroidism but this one does not, she's just a glutton who would eat 40 lbs. of food a day if I let her and regain all the weight she lost very quickly. Unlike the whippets she is not very fast (well, still faster than I am) but she can go all day for 20 miles or more easily, an incredible endurance athlete. Most of my other dogs are also more built for endurance and have a fairly slow metabolism which allows them to maintain weight on most foods. Dogs, more than many other species have been bred for extremes in looks and in function and are a good example to see how diverse their needs are in the area of nutrition. There is no reason to assume that there aren't major differences in the ways people's metabolism functions. I know some people who will not put on weight regardless of what they eat. Of course this does not mean that they are healthy regardless of what they eat, but calories in-calories out is not the same for everyone. Most people with thyroid issues struggle far more to lose weight and keep it off. There are dozens of hormones in our bodies that may play a role in what our bodies do with food. Jillian Michael's book "Master your metabolism" is a good introduction to endocrinology for people who are not in the medical profession and explains how more than 10 different hormones affect our weight.
I'm not sure where exactly I'm going with all of this, I want to do more research. But I think I have enough evidence to give a low-carb diet a try over the next few weeks. I'll make it even a little lower-carb than originally planned, shooting for under 50 grams of carbs. What percentage of my fat and protein intake will be animal (dairy, meat) and what percentage will be plant-based (nuts, coconut, olive oil, avocado) I don't know yet. But I will cut out all grain and beans and some fruit for a few weeks and see what happens. I will also continue to eat large amounts and a wide variety of raw vegetables and will eat mostly organic food, animal-protein from pasture-fed animals.