Exercício físico em jejum melhor para perder peso?

Com as devidas ressalvas (ver citação) o exercício parece ser mais benéfico (para perder peso) é o realizado de estômago vazio:

Why exercise might be more beneficial on an empty stomach

Citação:

"The scientists took blood samples after fasting and the high carb breakfast and then after exercise. They also took adipose (fat) tissue samples immediately before and one hour after the walking exercise.

They discovered that the expression of two genes (PDK4 and HSL) significantly increased when the men fasted – but decreased when the men ate a high-calorie breakfast before they exercised. The increase in these genes suggested that fat was used to fuel the exercise, instead of the food consumed at breakfast.

Dylan Thompson, corresponding author of the study explained that this fat tissue often faces competing challenges. After consuming food it is busy responding to the meal and "and a bout of exercise at this time will not stimulate the same [beneficial] changes in adipose tissue. This means that exercise in a fasted state might provoke more favorable changes in adipose tissue, and this could be beneficial for health in the long term."

Although the study supports previous research, it is worthwhile noting the study sample was small and only looked at overweight men."

Passar fome regenera Pâncreas (ajudando na diabetes Tipo 2)

Parecido com o livro sobre a reversão da diabetes tipo 2, há estudos que analisam o efeito da redução calórica (jejum) no pâncreas, parecendo que ajuda à sua regeneração e normalização dos níveis de açúcar no sangue:
http://www.bbc.com/news/health-39070183

Citando:
"Experts said the findings were "potentially very exciting" as they could become a new treatment for the disease.

People are advised not to try this without medical advice.

In the experiments, mice were put on a modified form of the "fasting-mimicking diet".

It is like the human form of the diet when people spend five days on a low calorie, low protein, low carbohydrate but high unsaturated-fat diet.

It resembles a vegan diet with nuts and soups, but with around 800 to 1,100 calories a day.

Then they have 25 days eating what they want - so overall it mimics periods of feast and famine.

Previous research has suggested it can slow the pace of ageing."

O estudo:
(published in the journal Cell)
http://www.cell.com/cell/fulltext/S0092-8674(17)30130-7