I see Subway sandwiches recommended a lot for dieting; why exactly are they helpful for weight loss?

Subway is popular for dieting because it allows for high nutritional customization. From a Western medical perspective, the core benefit is blood sugar management. Whole-grain bread options prevent 'glucose spikes.' When blood sugar rises sharply, the body secretes excessive insulin, which converts energy into stored fat; whole grains help block this process. Additionally, high fiber boosts metabolic efficiency by activating beneficial gut bacteria. In Traditional Korean Medicine (TKM), this approach is viewed as preventing the accumulation of Phlegm-fluid (Dam-eum), which are metabolic waste products that build up in the body. Consumption of overly spicy or salty foods can lead to Spleen Deficiency (Bi-heo), weakening digestive functions and causing edema (swelling) through the creation of Phlegm-fluid. Conversely, fresh vegetables and lean proteins revitalize the Spleen System (Bi-gye) and promote the smooth circulation of Qi and Blood. However, it is important to be cautious with sauces. Overloading on heavy dressings can lead to Qi Stagnation (Gi-che), causing bloating and a heavy sensation in the body. The process of selecting clean, natural ingredients that suit your constitution is the true essence of normalizing metabolism, which is the ultimate goal of a TKM-based diet.