It's been reckoned that the average American will gain 8 lbs over the Christmas holiday, and we don't suppose the average Briton is too far behind.
Many millions of pounds have been made by authors and organizations, all claiming to have found the ultimate diet. While many of them work for a while, most people regain the weight they had initially lost.
Those of us plagued by weight problems can probably recite the slimming rota - the high-fat, low-carbohydrate diet, the high-carbohydrate, low-fat diet, the Atkins diet, the calorie-counting diet, and so on.
So here's a piece of news that isn't so new - the best diet we've come across is around 150 years old, and was suggested by an ear, nose and throat specialist called Dr William Harvey, and popularized by its first success, William Banting, who wrote the first-ever slimming book.
Banting weighed 202 lbs, and was showing signs of serious diabetes - his sight was failing, and he was having hearing problems - when he met Harvey. Harvey was interested in the role that fats, sugars and starches played in diabetes, and in particular their effect on the liver which he knew secreted a sugar-like substance that it made from the blood passing through it.
Banting's diet was simple. He had to cut out all bread, butter, milk, sugar, beer and potatoes, as these contain sugar and starch that would be converted to fat. Otherwise, Banting could eat what he wanted, within reason. Every day he was allowed up to six ounces of bacon, beef, mutton, venison, kidneys, fish or poultry, the fruit of any pudding, but not the pastry, any vegetable except potato, two to three glasses a day of wine, and tea without milk or sugar.
Banting lost 1 lb a week for a year, and his hearing was restored.
Today, the nearest equivalent of the Banting/Harvey diet is the glycaemic index diet, pioneered, amongst others, by Dr Michel Montignac, and championed by pop poppet Kylie Minogue (just in case you want some brownie points from your kids).
It's a diet our own publisher has tried, and he's lost 28 lbs in five months. His friend, an 80-year-old, has lost 17 lbs and even those who have just taken out the bread and potatoes have found they have lost weight gradually, but impressively.
So, as you reach for those roast spuds on Christmas day, spare a thought for William Banting.