Obese people face a range of health problems. They include cardiovascular problems and joint issues. But there is new evidence to show that their efforts to build more muscle can be blunted as well. The amount of exercise which could be performed is also reduced for obese adults when compared to those with a regular weight.
A 2018 study shows slower protein synthesis for obese adults
Protein synthesis is important after a workout. Those who train consistently know the role of protein and amino acids in muscle development. A 2018 study[i] at the University of Illinois shows just how much impact obesity has on this process.
The new perspective on post-workout protein synthesis was based on a group of young adults which were separated into an obese group and into a regular body weight group. Researches choose a leg exercise to get answers. But interestingly, the subjects were not told to exercise both legs. Due to scientific data comparison, subjects were told to exercise a single leg. Doing 10-12 repetitions on a single leg allowed the scientists to relate protein synthesis in the trained leg, compared to the untrained leg.
The subjects were given 170 grams of pork after each workout. This equated to 36 grams of protein and 4 grams of fat. In comparison, a scoop of soy protein comes with 23g of protein. But the results of the study were not surprising to the researchers. While protein synthesis increased in both legs, the differences between the obese group and the non-obese group were considerable. Myofibrillar protein, responsible with muscle growth, was blunted in the obese group. Even if obese adults have more muscles, their metabolic rate is lower, especially compared to non-obese adults.
It is an important discovery for long-term health. Researchers underlined that muscle building and muscle repair, specifically after workouts, has implications in metabolic health. Physical performance can suffer as well.
The study also showed that the group of young adults considered obese was showing a reduced physical performance when compared to non-obese subjects. So what can be done in this situation for obese adults today?
It is important to understand that the study also makes a few recommendations which give hope to obese people. Lifestyle modifications are recommended. Regular exercise is a good place to start. This exercise routine could improve the synthesis of postprandial myofibrillar protein synthesis. Researchers also suggest further investigation for obese adults for an optimized protein synthesis post-exercise.
The new evidence on the reduced stimulation of myofibrillar protein synthesis after feeding and resistance exercise shows the impact obesity can have on obese people. With reduced protein synthesis, the physical performance of obese adults can suffer as well. A fast absorbing protein such as whey protein can be recommended after a workout.
However, obesity can actually reduce the effects of resistance exercises. In these conditions, the benefits of resistance training can be blunted for obese adults. The effects are considerably better for normal weight adults. It's also important to know that all the subjects recruited for the purpose of the study were not following a routine of physical exercise and they represent a selected group of people insufficiently active.
[i] J. Beals, S. Skineer, C. McKenna et a. (2018), Altered anabolic signalling and reduced stimulation of myofibrillar protein synthesis after feeding and resistance exercise in people with obesity, The Journal of Physiology. Available at: