The Great British Bake Off (TGBBO)—aka The Great British Baking Show in the US and Canada—features amateur bakers competing each week in a series of baking challenges, culminating in a single winner. The recipes include all manner of deliciously decadent concoctions, including the occasional Christmas dessert. But many of the show's Christmas recipes might not be as bad for your health as one might think, according to a new paper published in the annual Christmas issue of the British Medical Journal, traditionally devoted to more light-hearted scientific papers.

TGBBO made its broadcast debut in 2010 on the BBC, and its popularity grew quickly and spread across the Atlantic. The show was inspired by the traditional baking competitions at English village fetes (see any British cozy murder mystery for reference). Now entering its 15th season, the current judges are Paul Hollywood and Prue Leith, with Noel Fielding and Alison Hammond serving as hosts/presenters, providing (occasionally off-color) commentary. Each week features a theme and three challenges: a signature bake, a technical challenge, and a show-stopper bake.

The four co-authors of the new BMJ study—Joshua Wallach of Emory University and Yale University's Anant Gautam, Reshma Ramachandran, and Joseph Ross—are avid fans of TGBBO, which they declare to be "the greatest television baking competition of all time." They are also fans of desserts in general, noting that in medieval England, the Catholic Church once issued a decree requiring Christmas pudding four weeks before Christmas. Those puddings were more stew-like, containing things like prunes, raisins, carrots, nuts, spices, grains, eggs, beef, and mutton. Hence, those puddings were arguably more "healthy" than the modern take on desserts, which contain a lot more butter and sugar in particular.

But Wallach et al. wondered whether even today's desserts might be healthier than popularly assumed and undertook an extensive review of the existing scientific literature for their own "umbrella review." It's actually pretty challenging to establish direct causal links in the field of nutrition, whether we're talking about observational studies or systemic reviews and meta-analyses. For instance, many of the former focus on individual ingredients and do not take into account the effects of overall diet and lifestyle. They also may rely on self-reporting by study participants. "Are we really going to accurately report how much Christmas desserts we frantically ate in the middle of the night, after everyone else went to bed?" the authors wrote. Systemic reviews are prone to their own weaknesses and biases.

"But bah humbug, it is Christmas and we are done being study design Scrooges," the authors wrote, tongues tucked firmly in cheeks. "We have taken this opportunity to ignore the flaws of observational nutrition research and conduct a study that allows us to feel morally superior when we happen to enjoy eating the Christmas dessert ingredients in question (eg, chocolate). Overall, we hoped to provide evidence that we need to have Christmas dessert and eat it too, or at least evidence that will inform our collective gluttony or guilt this Christmas."

The team scoured the TGBBO website and picked 48 dessert recipes for Christmas cakes, cookies, pastries, and puddings, such as Val's Black Forest Yule Log, or Ruby's Boozy Chai, Cherry and Chocolate Panettones. There were 178 unique ingredients contained in those recipes, and the authors classified those into 17 overarching ingredient groups: baking soda, powder and similar ingredients; chocolate; cheese and yogurt; coffee; eggs; butter; food coloring, flavors and extracts; fruit; milk; nuts; peanuts or peanut butter; refined flour; salt; spices; sugar; and vegetable fat.

Wallach et al. identified 46 review articles pertaining to health and nutrition regarding those classes of ingredients for their analysis. That yielded 363 associations between the ingredients and risk of death or disease, although only 149 were statistically significant. Of those 149 associations, 110 (74 percent) reduced health risks while 39 (26 percent) increased risks. The most common ingredients associated with reduced risk are fruits, coffee, and nuts, while alcohol and sugar were the most common ingredients associated with increased risk.

Take Prue Leith's signature chocolate Yule log, for example, which is "subtly laced with Irish cream liqueur." Most of the harmful ingredient associations were for the alcohol content, which various studies have shown to increase risk of liver cancer, gastric cancer, colon cancer, gout, and atrial fibrillation. While alcohol can evaporate during cooking or baking, in this case it's the cream filling that contains the alcohol, which is not reduced by baking. (Leith has often expressed her preference for "boozy bakes" on the show.)

By contrast, Rav's Frozen Fantasy Cake contains several healthy ingredients, most notably almonds and passion fruit, and thus carried a significant decreased risk for disease or death. Ditto for Paul Hollywood's Stollen, which contains almonds, milk, and various dried fruits. "Overall, without the eggs, butter, and sugar, this dessert is essentially a fruit salad with nuts," the authors wrote. That is, of course, a significant caveat, because the eggs, butter, and sugar kinda make the dessert. But Wallach et al. note that most of the dietary studies condemning sugar focused on the nutritional effects of sugar-sweetened beverages, and none of TGBBO Christmas dessert recipes used such beverages, "no doubt because they would have resulted in bakes with a soggy bottom."

The BMJ study has its limitations, relying as it does on evidence from prior observational studies. Wallach et al. also did not take into account how much of each ingredient was used in any given recipe. Regardless of whether the recipe called for a single berry or an entire cup of berries, that ingredient was weighted the same in terms of its protective effects countering the presumed adverse effects of butter. Would a weighted analysis have been more accurate? Sure, but it would also have been much less fun.

So, is this a genuine Christmas miracle or an amusing academic exercise in creative rationalization? Maybe we shouldn't overthink it. "It is Christmas so just enjoy your desserts in moderation," the authors concluded.

BMJ, 2023. DOI: 10.1136/bmj‑2023‑077166  (About DOIs).