When Sex Was Sold as a Diet Plan
- JELQ2GROW
- Sep 4
- 3 min read
In 1972, Dr Abraham I Friedman made headlines with a simple catchphrase, “reach for your mate, not your plate.” His book How Sex Can Keep You Slim landed at the perfect moment, when fad diets, exercise crazes, and anything to do with sex were selling out bookstores. The idea was bold enough to grab attention and playful enough to make readers curious. But could it actually work?
Friedman pointed to one patient, “Sally,” as proof. She developed a sweet tooth after her husband’s death, lost the cravings when she remarried, then returned to junk food after her second husband’s heart attack ended their sex life. From this case, he concluded that food was often a substitute for intimacy and that more time in bed meant fewer late-night snacks. The pitch wrote itself, and the public bought it.
Sex and the calorie question
Friedman’s formula looked neat on paper. Sex, he claimed, burned 200 calories, while snacks added 700. Replace one with the other and you saved 900 a night. The problem is that the body does not play along with that arithmetic.
Modern research puts the calorie burn much lower. Frappier et al., writing in PLOS ONE in 2013, measured couples at home with sensors and found that men spent about 101 kilocalories per session, women around 69, with an average rate near 3.6 kilocalories per minute. A systematic review in 2022 confirmed that a typical encounter burns close to 100 calories, and Zavorsky in 2019 found about 130 on average, though over shorter sessions; a handful of men in unusually vigorous sessions managed to burn over 300. Those cases were the exception, not the rule, and they show how much duration and effort can change the totals.
In this sense, duration matters. Many encounters last around six minutes, which adds up to about 20 calories total. To reach the numbers Friedman promised, you would need extended sessions of 40 minutes or more, the kind that are closer to exercise than to a quick tryst.
If you actually want to burn calories
Research shows the burn depends on duration and intensity. In the PLOS ONE study by Frappier, couples who went longer, with foreplay included, spent two to three times more energy than average. Zavorsky later recorded some men passing 300 kilocalories during especially vigorous encounters, even beating their treadmill sessions.
The other big factor is workload. Positions where one partner carries more of their own weight demand more muscle and push the total higher. Think of a woman astride as a squat in disguise, or missionary for the partner on top as a mix of push-up and plank. The principle is simple: the more active the role, the more calories it costs.
Beyond the numbers
The studies also reveal that sex, while not a substitute for a gym routine, does count as moderate-intensity activity. Frappier measured an average of 5 to 6 METs, similar to brisk walking or light cycling, and peaks can push into vigorous territory. Heart rates rise into the 90 to 130 range, sometimes climbing near 170 at climax. Positions matter too, with more active or weight-bearing roles raising the metabolic bill.
So yes, sex burns calories, but usually not enough to replace a run. And while it may save you from a soda and chips now and then, hunger eventually returns. Friedman’s line that “if the sexual act has been successful, there’s no thought of food” sounds clever, but it does not match how appetites actually work.
The larger flaw was frequency. Even the most active couples average one to three sessions a week, singles far fewer. As a daily diet plan, the math collapses quickly.
Two years later, Friedman released Fat Can Be Beautiful, this time warning against the damage of fad diets. Coming from the same man, it almost reads as self-parody.
What survives is less a health plan than a snapshot of its era. Sex does have real physiological benefits: calorie burn, cardiovascular stimulation, hormone release, and intimacy that no treadmill delivers. But Friedman’s promise of slimming down through nightly passion was a sales pitch first and science a distant second.
Nice article