Chubby folk are more content, he knew, and exude an air of bonhomie and good fellowship: 'Sleek-headed doctors and such as sleep a-nights.' In Samuel Shem's The House of God, the Fat Man bestrides the hospital like a colossus, a jolly green blimp generously dispensing wisdom and comfort.
In contrast, as Caesar again almost said: 'Cassius has a lean and hungry look. He thinks too much. Such doctors are dangerous.'
But not everyone agrees. GPs should maintain a healthy weight, as patients may ignore doctors who do not follow their own advice, according to England CMO, Professor Dame Sally Davies. 'I am perpetually surprised by how many GPs are overweight,' she said. 'It suggests they haven't taken on board the health messages and their employer is not supporting them enough to lose weight.'
It was 'human nature', she added, for patients to question what could be seen as hypocritical health advice from GPs.
In February 2013, Dame Sally was rated the sixth most powerful woman in the UK by the BBC Radio 4 programme Woman's Hour.
Her salary (£210,000) was the second highest in the NHS in 2013. Before this, Dame Sally was a haematologist, which obviously accounts for her in-depth knowledge of obese GPs. The only haematologist I ever remember meeting was a chubby yet charming person, who also knew nothing about general practice.
The accusation of hypocrisy is, I admit, fair comment. For example, I advise patients to follow a Mediterranean diet, but I love cream buns. I advocate taking more exercise, but I prefer my armchair in front of the fire.
But hey, being a hypocrite isn't so bad, there are worse vices than hypocrisy. To paraphrase Brutus, before the Battle of Philippi: 'If we do meet again, why, we shall smile. If not, why then this jam doughnut was well made.'
- Dr Farrell is a GP from County Armagh. Follow him on Twitter @drlfarrell