Partway through her Diary of a CEO conversation, after a good defence of carbohydrates against the people who treat them as poison, Dr Stephanie Estima says three words we want to talk about: 'we need carbohydrates'. Not most people do well with some. Not restricting them long-term has trade-offs. We need them, she says, for mood, for sleep, for performance in the gym, and she gestures at the thyroid on the way past.
We love this doc. She is well respected, and most of this episode we would hand to a friend without a second thought. This is the one place we part ways.
The body makes its own glucose
The trouble is the phrase we need carbohydrates, because it collapses a real distinction. The body does need glucose. It does not need you to eat it. Of the three macronutrients, dietary carbohydrate is the only one with no essential minimum: there are essential amino acids and essential fatty acids you will eventually suffer without, and there is no essential carbohydrate. The body makes the glucose it requires from protein and other substrates through a process called gluconeogenesis, which is why people on long-term low-carbohydrate and ketogenic diets do not simply run out of fuel. This is the same point Dr David Unwin made in the conversation we wrote up recently, where he has helped people reverse type 2 diabetes by lowering a carbohydrate load their bodies were struggling to handle.
The thyroid deserves more than a wave
The thyroid point needs more than a passing gesture, in both directions. It is true that some people, especially women who are under-eating overall, see thyroid hormone conversion slow on very low carbohydrate intakes, and that is a real signal worth respecting. It is also individual, dose-dependent, and often as much about total energy as about carbohydrate specifically. Treating it as proof that everyone needs a set amount of bread flattens exactly the complexity she spends the rest of the episode defending.
Weight is regulated by hormones
The deeper place we diverge is the move to calories. Estima describes losing belly fat as a matter of calories in, calories out, and even calls the model somewhat oversimplified before leaning on it anyway. Weight is regulated by hormones - insulin chief among them - not by arithmetic alone. Two people can eat the same number of calories and store them very differently depending on how much insulin those calories provoke, which is precisely why the type and timing of a carbohydrate matters and not only the total. A baked potato, to borrow Unwin's framing, can land in the bloodstream a lot like several teaspoons of sugar. The calorie count will not tell you that. Your glucose response will.
None of this makes carbohydrate the enemy. Someone training hard, sleeping well, and metabolically healthy can use carbohydrate as fuel, and timing it around a workout - the way Estima describes eating before she trains - is one of the better uses of it. The question is never carbs, yes or no. It is which carbohydrates, how many, when, and for whom. For someone with insulin resistance or type 2 diabetes, being told they need carbohydrates can be the opposite of the advice that would actually help.
What we would keep from Estima is the instinct underneath the claim: that women have been starved, scared off food, and handed rules that broke their metabolism rather than fixed it. Eating enough matters. Fearing food is its own harm. We just would not reach for 'you need carbohydrates' to make that case, because the body has been making its own glucose the whole time.
Watch the full conversation: Dr Stephanie Estima on The Diary of a CEO.