Weightless: A Doctor's Guide to GLP-1 Medications, Sustainable Weight Loss, and the Health You Deserve

Weightless is a breezy guide to GLP-1 drugs by a New York City based endocrinologist and obesity specialist. Dr. Salas-Whalen has been working in this field for decades, and she firmly believes that obesity is primarily a hormonal problem and GLP-1 drugs are the solution. As such, she has her interests, but they’re clearly laid out: use these drugs under the supervision of a physician, preferably an obesity specialist like her, use only FDA approved formulations. And most importantly, GLP-1 are only one part of weightloss; a high protein diet and strength training are the other two parts.

I was most interested in the science. GLP-1 is literally Glucagon-like peptide-1, a hormone identified in the early 1980s which plays a key role in modulating digestion, blood sugar, and feeling full after meals. Natural GLP-1 breaks down in minutes, and it took decades to develop the first workable drugs, which were for treatment of diabetes. The first generation required injections 30 minutes before breakfast and dinner, so compliance was basically nil. Around 2020, Ozempic and Wegovy broke into mainstream awareness, which had the potential of once a week injections or daily pills.

Dr. Salas-Whalen discusses the differences between semaglutide and tirzepatide, which is newer and works on two hormone pathways. These drugs are best titrated up to a therapeutic dose, both to limit side effects and get more out of the weightloss plateau before the patient adjusts to the drug. Some digestive problems, especially diarrhea and heart-burn are very common, and other side effects are genuinely a reason for medical concern.

While GLP-1 make it possible to lose weight by reducing “food noise” and emotional eating, getting the most out of the drugs requires eating 100 grams of protein per day, ideally in 4x meals of 30 grams each, which is a lot of protein. And strength training is still strength training.

Dr. Salas-Whalen is relentlessly pro-GLP-1, to the point where I’m concerned she’s actively ignoring any contrary evidence. And I think everything useful in this book could be said in 50 pages. As with anything novel and popular, there’s more smoke than light.