Obesity and Gut Microbiota

*Arslan Ahmad, Sakhawat Riaz and Muhammad Tanveer*

### **Abstract**

Obesity is a severe worldwide health problem driven by both hereditary and environmental factors, and its prevalence is increasing year after year. According to current thinking, The bacteria in the stomach may have a part in the growth of obesity and other health comorbidities. To better fully comprehend the link between obesity but also microbiomes, we sum up the features of the intestinal microbiota in obese people, the metabolic pathway of obesity-induced by the intestinal microbiota, and the impact of biological factors on the intestinal microbiota and adiposity in this chapter. The microbiome has been shown to have a major role in the development of obesity by regulating energy metabolism. The makeup and density of intestinal flora can be influenced by diet. Simultaneously, it is suggested that the gut microbiome be used in obesity studies. Some food items have recently shown that pro capability via functional ingredients that impact the intestinal flora, attracting the interest of scientists.

**Keywords:** obesity, weight loss, intestinal microbiota, diets

### **1. Introduction**

Obesity is a physiological condition triggered by a mixture of hereditary and nongenetic variables, such as external cues. Obesity is classified by the World Health Organization as having a Body fat percentage of more than 30, however, the requirements vary by country. In China, for instance, obesity is classified as a BMI of 28 or more. Over one-third of the worldwide population is overweight, including over 10% obese, according to a thorough survey [1]. Obesity is estimated to reach 1.12 billion people worldwide by 2030 [2]. Obesity affects more than 500 million people worldwide, creating a major financial and public-health issue [3]. Obesity has sparked renewed worry and is now becoming a severe global health issue. Obesity is associated with abnormalities in triglycerides, insulin, inflammatory processes, and peroxidation, as well as a higher risk of heart disease, diabetes, and malignancy [4, 5]. According to a rising body of evidence, a bacterial imbalance in the gut contributes to obesity [6, 7]. Dietary changes, exercise, surgery, and medication are the most popular treatments for obesity. Traditional weight loss techniques, on the other hand, frequently fail to produce satisfying results, and obesity rates are expected to climb further [8]. Many dietary plants have been proven to reduce appetite, restrict food absorption, reduce adipogenesis, and increase energy consumption, and all have anti-obesity properties [9]. In the human intestinal mucosa, particularly the colon, the gut microbiota, which contains bacteria, fungi, Archea, and viruses, is common [10, 11]. The effect of gut microbiota on obesity

has received a lot of attention in current history, and it might be a viable weightloss strategy. The effects of food plants on gut flora have recently received a lot of emphasis. The gastrointestinal microbiota contains around 100 trillions of commensal bacteria, which is 10 times the body's total density [12].

To keep its birthrates high, the gut flora feeds on nutritional remnants that people cannot process, mucous secreted either by the gut, and cells waste shed as food [13]. Short-chain fats, nutrients, and right things like a pro, analgesic, or oxidative chemicals will be produced by a healthy gut bacteria, along with potentially dangerous items such as neurotoxicity, malignancies, including immunotoxins [14, 15]. Such substances can infect humans, and immediately cause mutations, thus disrupting the defense but also physiological processes of humans. As a consequence, maintaining the body's natural normal metabolic equilibrium need balanced intestinal bacteria. Obesity is regarded as a long net caloric consumption mismatch that results in excessive weight gain [16]. The interplay between biological and epigenetic variables, such as nourishment, dietary components, and/or lifestyle decisions, are to blame. Overall, the complex mechanisms that lead to obesity and its consequences are unknown, but recent research shows that it gastrointestinal tract the thousands of microorganisms that normally reside within the individual gastrointestinal tract should be taken into account [17]. Food absorption, energy management, and fat storage are all influenced by the intestinal microbiota and its microscopic genome, according to a new study.

Moreover, gut flora can alter the immune system of humans [18], and also the composition of bile salts, which can affect ingestion and physiology [19]. Obesity, cancer, and irritable bowel syndrome are hypothesized to be caused by gut microbial dysbiosis [20, 21]. Gram-negative bacteria lipopolysaccharide (LPS) may, for instance, produce an immune response in the recipient [22]. Obese people have a lesser variety of intestinal flora than lean people [23], and the huge quantity of specific gut microbiota taxa has changed in obese people [24]. Utilization of some food items could be negatively proportional to excess weight through modifying gut flora, according to epidemiological research [25–27]. As a consequence, eating dietary plants and taking advantage of their impact on gut microbiota management might be a novel method to treat obesity. These results indicate that gut bacteria may regulate the host's energy metabolism, potentially leading to obesity and other disorders. This chapter's vision is to offer a broad review of this hot issue, including the involvement of the intestinal microbiota with obesity.
