The Carbohydrate-Insulin Model: Is It Too Simple?

However, he said it is not a magic elixir, and generating significant weight loss by exercise alone with no intentional reduction in energy intake is rarely successful. But Dr Braun explained that exercise is critical to maintaining weight loss. When looking at the characteristics of people who have lost a significant amount of weight, those who maintained that weight loss generally average 45 to 60 minutes of exercise per day.

“A modest amount of exercise is generally compatible with either a low-fat or low-carbohydrate diet. For people who are doing a lot of daily exercise (eg, more than an hour a day and/or high-intensity training), the high demand for carbohydrate to fuel activity may drive a need for more carbohydrate than a really low-carbohydrate diet can provide,” Dr Braun told Endocrinology Advisor.

The Evidence

In general, the differences in low-fat vs low-carbohydrate are subtle when it comes to exercise, according to Dr Braun, who noted that blanket recommendations are less important than the individual dynamic.

“The physical, mental, and emotional health benefits of exercise are so potent, even without weight loss,” said Dr Braun. “Endocrinologists should try to convince their patients to become more active, irrespective of weight loss, dieting, or not dieting.”

Dr Braun said that simply breaking up “sitting time” can have a healthful effect. Dr Thomas agreed, noting that this perhaps is the simplest prescription an endocrinologist could use when counseling new patients. 


  1. Ludwig DS, Hall KD, Braun B. Macronutrients, calories, or physical activity? Game of truths. Presented at: ObesityWeek 2016; October 31-November 4, 2016; New Orleans, LA.
  2. Lin P-J, Borer KT. Third exposure to a reduced carbohydrate meal lowers evening postprandial insulin and GIP responses and HOMA-IR estimate of insulin resistance. PLoS One. 2016 Oct 31. doi:10.1371/journal. pone.0165378.