Atherosclerosis—considered the major cause of cardiovascular diseases (CVDs)—is strongly associated with obesity, to which it strongly contributes. Moreover, atherosclerosis is characterised by a long asymptomatic phase, and its progression can lead to serious cardiovascular (CV) events. The carotid intima-media thickness (cIMT) has been determined as a predictor of CV events, as well as a marker of subclinical atherosclerosis, and has been used in clinical trials as an alternative assessment method or a surrogate endpoint. It should be noted that several behavioural approaches can directly influence the cIMT values, and decrease or increase the CV risk. In our paper, we aimed to summarize the current knowledge regarding IMT measurement among patients with obesity as a risk group—also in terms of the obesity paradox where the diagnosis of subclinical atherosclerosis is especially essential and implements the early therapeutic approach. We also summarized behavioural, modifiable factors, such as the Mediterranean diet, the Dietary Approach to Stop Hypertension Diets, body weight reduction or the intake of micro- and macronutrients, with a particular focus on the studies where the cIMT values were one of the outcomes. In order to collect the literature data related to the presented topic, the PubMed database was explored.