Weight and food blogs abound on the Internet and everyone from bloggers to related comments is passionate about which diet worked for them. The great debate is right now is low carb vs. low fat. There are the carbophobes, fatphobes, food faddists and the ever-present diet products, supplements and gimmicks.
Everyone has a theory even though I doubt many of them are biochemists, endocrinologists, or have degrees in human physiology. Some people are just using common sense – how refreshing. After trying to remember my biochemistry courses, I realized that I learned a little but just enough to make me realize that I basically know nothing about how and why we get fat. What I have learned is that the process is very complex as well as losing the weight and keeping it off.
- We eat too much and move too little.
- We eat too many processed foods containing the villains, sugar and fat (and salt).
- Food is all around us in ways that humans have never experienced before.
- We follow every fad diet that is out there hoping that this one will be the magic bullet we’ve been waiting for.
- We eat too fast and never let our brains know we are full.
- Our body weights and body types are influenced by our genetic makeup.
- Our bodies try to protect us from starvation at all costs when we do diet
- Some people remain thin.
Here’s what the current research says:
Research has found that genes do play a role in obesity whether they increase the risk or decrease the chances that someone will become overweight and/or obese. In one study, 18 new gene variants were linked to obesity and confirmed the presence of 14 others. Another study identified 13 gene variants that influenced whether fat appeared on the belly or thighs, helping to confirm our theories of apple or pear body shapes. Among these genes, seven had a stronger effect on women than men (no surprise).
If a person has more of these variants, they have a greater risk of becoming obese, but it does not mean they will always become obese. The genes appear to act in the brain in concert with environmental influences, i.e. whether they turn on or off and no one knows what those influences are (yet). When mice with the same genetic makeup (inbred) were placed on a high-fat diet, some gain more weight than others. When you exercise them by running on a wheel, some run more than others. So animals with the same genes display different body weights and exercise habits.
Obesity expert Dr. David L. Katz, director of the Prevention Research Center at Yale University School of Medicine, said, “Let us by all means study our genes, and their associations with our various shapes and sizes,” “But let’s not let it distract us from the fact that our genes have not changed enough to account for the modern advent of epidemic obesity — our environments and lifestyles have.”
The best example lies with the Pima Indians who basically have a lot of genetic similarity. One group lives in Arizona and 75% of them are overweight or obese and of them, 45% have diabetes type 2. Another group lives in Mexico and most of them are not overweight and have a 6% rate of diabetes. Guess who has the healthiest diet – the Mexican Pimas. They eat real food and have to work a little harder to obtain it than their Arizona counterparts. Arizona Pimas eat the typical American diet of fast food loaded with sugar and fat. No surprise here.
We are just beginning to understand the role of hormones in weight regulation and eating behavior. Leptin is the most studied but there are several others. Leptin is produced by fat cells and tells the hypothalamus in the brain when the body has plenty of fat stores. When people lose weight, their leptin levels also decrease. The hypothalamus thinks the body is starving and promotes more food intake and less energy expenditure to prevent starvation. Hunger drives the individual to eat and thus weight maintenance is difficult.
Some interesting research suggests that in some cases a virus, primarily the adenovirus 36, causes obesity. In animals (chickens, mice and non-human primates) this virus increases fat stores. Thirty percent of obese people have antibodies to this virus compared to only 11% in non-obese people.
There is also some research suggesting that the kind of gut bacteria may influence your weight status. Transplanting feces from a thin animal to a fat one reversed the obesity and transplanting feces from a fat animal to a thin one made the thin one fatter. Diet, especially fiber can influence what kinds of bacteria reside in the gut.
Some medications can cause weight gain. In a new study, Australian researchers found that among more than 11,400 adults with high blood pressure and/or diabetes, those on some older beta-blockers weighed more, on average, and had larger waistlines. And in a study of 30 patients with high blood pressure, they found that people on beta-blockers generally burned fewer calories and fat after a meal.
So, weight gain and loss is not so simple after all as some say – eat less, move more may be true for some people, but for others, there are factors beyond their control that must be understood before they are judged too harshly for their weight status.