Among factors that result in weight loss (or not) are stress levels. High stress levels can cause the release of cortisol, the stress hormone, and contribute to metabolic risk factors such as central obesity. Motivations also play a role.
Still, it is hotly debated as to which diet is best – for both weight loss and overall health. Let’s look at the evidence.
Low-carb vs. low-fat diets
Is a low-carbohydrate, high-fat diet a fad? In a 12-month randomized controlled trial (RCT), results showed that a low-carbohydrate diet was better at reducing weight than low-fat diet for those who were obese or morbidly obese, by a mean difference of 7.7 pounds.
The authors also note that the low-carbohydrate diet reduced cardiovascular disease risk factors in the lipid (cholesterol) profile, such as decreasing triglycerides and increasing HDL (good cholesterol).
Patients lost 1.5 percent more body fat on the low-carbohydrate diet, and there was a significant reduction in the inflammation biomarker C-reactive protein (CRP). There was also a reduction in the 10-year Framingham risk score, which estimates cardiovascular risk.
However, there was no change in LDL (bad cholesterol) levels or in truncal obesity in either group.
Digging deeper into the diets used, it’s interesting to note that the low-fat diet was remarkably similar to the standard American diet; it allowed 30 percent fat, only 5 percent less than the 35 percent baseline for the same group.
In addition, it replaced the fat with mostly refined carbohydrates, including only 15 to 16 g/day of fiber. Meanwhile, the low-carbohydrate diet participants took in an average of 100 fewer calories per day, so it’s no surprise that they lost a few more pounds over a year’s time.
As Dr. David Katz, founding director of Yale University’s Prevention Research Center, noted, this study was more of a comparison of low-carbohydrate diet to a high-carbohydrate diet than a comparison of a low-carbohydrate diet to a low-fat diet.
Comparing health impacts
Interestingly, in a meta-analysis of 48 RCTs, results showed that whether a low-carbohydrate diet (including the Atkins diet) or a low-fat diet (including the Ornish plant-based diet) was followed, there was a similar amount of weight loss compared to no intervention at all.
Both diet types resulted in about 17.6 pounds of weight loss at six months versus no change in diet.
In an accompanying editorial, the author points out that it is unclear whether a low-carbohydrate/high-animal protein diet might result in adverse effects on the kidneys, loss of calcium from the bones, or other potential health risks.
The author goes on to say that, for overall health and longevity and not just weight loss, micronutrients found in nutrient-dense foods may be the most important factor.
Finally, the type of motivator is important, whatever our endeavors. Weight loss goals are no exception.
A published study followed West Point cadets from school to many years after graduation and noted who reached their goals. The researchers found that internal motivators and instrumental (external) motivators were very important.
The soldiers with an internal motivator, such as wanting to be a good soldier, were more successful than those who focused on instrumental motivators, such as wanting to become a general. Those who had both internal and instrumental motivators were not as successful as those with internal motivators alone.
When it comes to health, focusing on an internal motivator, such as increasing energy or decreasing pain, could ultimately lead to an instrumental consequence of weight loss.
There is no question that dietary changes are most important to achieving sustained weight loss. However, we need to get our psyches in line for change.
Hopefully, when we choose to improve our health, we don’t just focus on weight as a measure of success. Focus, instead, on improving your health.