The biggest problem is that most "fitness gurus" (male and female) are products of steroid and HGH abuse while the programs and advice they're peddling are bunk if you're not juiced. You can totally shed fat and maintain muscle by cutting out carbs completely if you're injecting synthetic testosterone into your body. Otherwise, you'll catabolize lean mass no matter how much protein (and adults don't need that much protein) you consume. I speak as someone who juiced consistently for a decade, so I know all the tricks. Everything they preach is misdirection from the truth at your expense.