Obesity is a worldwide problem in last year’s even it reached epidemic levels and it turns into some disease that related in obesity directly or indirectly in all body organs. Obesity factors can be inappropriate diet, genetically factors, gut microbiota, sex, age. These factors change to gut microbiota composition ,  The human gut microbiota is including 10 billion bacterial cells. Bacterial cells digest to some nutrient which is not able to digest normally in the intestine. Firmicutes bacteria is an example for digestion to non-digesting carbohydrate. During the digestion process in the firmicutes bacteria metabolisms, the short-chain fatty acids (SCFA) is produced. SCFA gives more energy than carbohydrates. Additionally, SCFA has used substrates for signal pathways. these signal pathways regulate the intestinal permeability, ıntestine length, satiety, hunger, insulin resistance etc. Therefore, the higher amount of firmicutes bacteria in gut microbiota gives more energy and ultimately obesity ,  Obesity is playing the fundamental key role of regulation of gut microbiota. This regulation gives to some advantages to one class/genus/species of bacteria while the other bacteria affect harmfully. At the same time, the human gut microbiota, including all prokaryotic cells, effects to diet type reversely. This process can be called “Self-Domino Effect”. Diet effects on gut microbiota and, gut microbiota effects to food uptaking, diet. So, they may be triggered/regulated by itself in uptaking food . However, it is hard to people. Probiotic bacteria and prebiotics can modulate to gut microbiota for resembling fewer firmicutes bacteria composition. Because in the obese person, firmicutes bacteria abundance in the gut microbiota is very level while in the lean or normal weight person gut microbiota has fewer firmicutes/bacteroidetes ratio bacteria. Lactobacillus and bacteroidetes bacteria are one of the probiotic bacteria types , . Probiotics and prebiotics can break the “Self-Domino Effect” to prevent obesity. On treatment approaches to obesity, the main concepts are changing to gut microbiota composition for giving advantages probiotics bacteria for decreasing the abundance of firmicutes bacteria. For break, the “Self-Domino Effect”, prebiotic nutrient, probiotics bacteria can be used.