The gut microbiome (GMB) plays a significant role in human health. The current book chapter delves into the complex interactions between the diet and the gut microbiome makeup to highlight their combined effects on microbial diversity and the physiology of the host. Fibre-rich diets, like the Mediterranean diet, significantly increase the abundance of beneficial species like Bifidobacterium and Faecalibacterium and increase the short-chain fatty acid production which strengthens the gut barrier and helps in decreasing inflammation. Macronutrients (carbohydrates, proteins and fats) show a differential effect on microbial composition along with plant-based proteins and unsaturated fats being beneficial to health. However, animal-based proteins have the potential to aggravate dysbiosis. The metagenomics-driven personalized nutrition adjusts dietary interventions based on the individual microbiome profile to achieve optimal health outcomes. In addition, nutrition is brought into a very prominent limelight on its important role of modulating the microbiome present in the gut, as substantial evidence-based information is presented on how diet should be advised to slowly become a part of the healthcare history to slow down and inhibit the risk of chronic diseases by modulation of the microbiome in the gut. In conclusion, the current book chapter highlights the significant role of nutrition in modulating the GMBs by providing evidence-based insights for dietary recommendations and microbiome-targeted therapies to promote health and mitigate chronic disease risk.