Prolonged Weight Loss Plateau

Patient: Hey, my name’s Ariana, and I’m 17 years old. I was overweight for most of my life, until I decided to get fit. I went on a reduced calorie diet and started exercising 6 days a week. So, for the past year and a half, I’ve been consuming about 400 calories Monday through Thursday, about 800 calories on Friday, and normal intake on Saturday and Sunday. I lost about 50 pounds that way, but for the past 4 or 5 months, I’ve been plateaued. I haven’t lost any significant weight, and I’m worried that my body is in starvation mode. I’m 5’6” and I weight 134 pounds. I want to be 115 lbs, but I’m not losing any weight. Recently, I’ve decided to consume no more than 400 calories all 7 days of the week. I also joined a gym a couple of months ago to amp up my work out. I work out there 6 days a week and burn about 500-520 calories per session. It’s been about a week and a half of the 400 calories all 7 days diet, so I know I still need to give it time. Still, I don’t understand why I’m not losing any more weight. Could you please give me some suggestions to jump start my weight loss back? Thank you so much!