Starvation mode - about as real as Theon Greyjoy's penis. "I'm eating nothing and my weight hasn't changed - I must be in starvation mode..." Cliff notes 👉 you're not. Being immune to starving isn't a thing. What is actually happening, assuming you are accurately monitoring your caloric intake in the first place - is something called Metabolic Adaptation. Your metabolism is made up of multiple component parts, including your Basal Metabolic Rate (BMR), Thermic Effect of Food (TEF), Exercise Activity Thermogenesis (EAT) and Non Exercise Activity Thermogenesis (NEAT) - when you reduce your caloric intake and you being to lose weight, these components down regulate in order to maintain homeostasis - so as much as you may want a sweat soaked adonis-like six pack, you're body really doesn't. Each component within your metabolism adapts in a different way; your BMR is directly influenced by your overall body mass, so as you begin to lose weight, your BMR lowers - albeit this is one of the least adaptive components of your metabolism. On the flip side, the most adaptive and influencial component of your metabolism is your NEAT. When your NEAT down regulates - you move less, both consciously and subconsciously - meaning you're expending less energy - burning fewer calories. This is usually one of the biggest adaptive mechnicasms that causes people's fat loss progress to stall. So what do you do to address these adaptations? 👇 The simpliest strategy to implement, aside from 'moving more', would be a short term refeed, where you bring your caloric intake up to your maintenance, to allow these adaptive changes such as a reduction in your NEAT and an increase in stress hormones to lessen. That, if programmed over a specific length time, is a very basic introduction to nutritional periodisation. There are also some distinct Individual differences in metabolic adaptation to be aware of aswell. Some people can progress well for a substantial amount of time with a moderate deficit before adaptions occur and changes are needed - likewise some people adapt almost immediately when they begin to lose weight - It's all incredibly individual.