Weight Gain Attributed to Eating Meat?
One of the many benefits of consuming a plant-centered diet is that it reduces body fat and helps us maintain a healthy weight. Studies confirm that individuals consuming diets based on animal products have more abdominal fat and higher BMI's than their plant-based counterparts. Because meat, dairy and eggs are higher in calories, it's assumed that the concentrated calories are to blame. Although animal products do contain more calories, Dr. Michael Greger's video suggests that protein from animal sources is an additional factor.
In order to test whether or not weight gain is due to the excess calories in meat, hundreds of thousands of men and women spanning 10 countries were followed over a 5 year period in the EPIC-PANACEA study. This study was one of the largest studies on human nutrition ever performed. The study controlled calorie intake, so that they could determine whether or not consuming meat was associated with weight gain. This means that the group including meat in their diet ate the same number of calories as the group that did not consume any meat. Even after controlling for calories, the group that included meat gained weight. After five years and adjustment for total energy intake and underlying dietary patterns, the researchers concluded: "Total meat consumption was positively associated with weight gain in men and women, in normal-weight and overweight subjects. Our results are therefore in favor of the public health recommendation to decrease meat consumption for health improvement [and weight management]."
Consequently, those eating meat every day will gain 5 pounds every 2 years. This would explain why men and women have gained a significant amount of weight by the time they reach their 40's - 50's and 60's. Interestingly, "The strongest relation with annual weight gain--was observed for poultry." See Dr. Michael Greger's video regarding poultry and weight gain here and here.
Another point to consider is that any type of meat such as beef, pork and poultry stimulates substantial insulin secretion. In fact, "meat protein causes as much insulin release as pure sugar." Those who consume meat have up to 50% higher insulin levels whereas vegetarians have significantly lower insulin levels. High insulin levels encourages the storage of fat, thus promoting obesity.
As to be expected, members of The National Cattlemen's Beef Association were not pleased with the EPIC-PANACEA study findings. One of the speakers representing the association contacted the American Journal of Clinical Nutrition concerned that "meat intake's influence on body fatness cannot be assessed without measurement of body fat." To comply with their request, the researchers reviewed 91,214 of the participants from the study and specifically measured abdominal obesity and not overall obesity. The results were still the same. Abdominal fat was associated with meat consumption.
Subsequent studies in Spain and Belgium have confirmed the same results. The study from Belgium concluded that "Animal protein intake was associated with a bigger body mass index and waistline; whereas plant protein intake was associated with a smaller BMI and slimmer waist, indicating that the intakes of plant protein could offer a potential protective effect against overweight and obesity."