How Many Calories Are in Gin & Diet Tonic?

Gin and tonic is a classic cocktail being newly discovered by millennials and post-millennials. This drink is also popular with people of any generation who'd like to shed a few pounds because gin and tonic calories are low. The calorie content in gin and diet tonics is even lower.

If you love cocktails, but find yourself asking "What's the best alcohol to drink on a diet?", you'll want to know that gin and tonic calories are higher when used with regular tonic water. Tonic water calories differ slightly by brand. Generally, there are approximately 35 calories in 100 milliliters of tonic water (about a half cup), according to the USDA.

Regular tonic water isn't the best choice because it contains either sugar or high fructose corn syrup. Diet tonic water, on the other hand, is a no-calorie sugar substitute. This means it will have zero calories. For example, a Walmart brand of diet tonic water uses aspartame, a common sweetener, instead of sugar or corn syrup.

A shot of gin, typically what's in a single gin and tonic, delivers 97 calories. This equals 42 grams, or about 1 1/2 ounces. So if you're mixing gin with diet tonic water, you'll only get 97 calories. The same total goes for the calories in gin and soda water, or club soda, which has few or no calories.

Read more: The 13 Worst Alcoholic Drinks Sure to Derail Your Diet

A gin and diet tonic water is a low-calorie drink, as far as cocktails go. But according to Harvard T.H. Chan School of Public Health, alcohol can be both a "tonic and a poison" depending on how much is consumed. While moderate drinking can be good for your heart and blood circulation, heavy drinking is a major cause of preventable death in most countries.

Moderate drinking is typically no more than one drink a day for women and two drinks per day for men, as noted by the Harvard article. One drink of a spirit like gin is defined as one shot, or 1 1/2 ounces.

Heavy drinking can inflame and scar your liver. It may damage your heart muscle and increase your blood pressure as well. Even moderate drinking can interrupt sleep and interact negatively with medications.

Alcoholic beverages contain the molecule ethanol, which may have harmful effects on the stomach, brain, heart, gallbladder and liver. It may also increase your cholesterol and insulin levels and affect your mood and concentration. Harvard T.H. Chan School of Public Health states that if you drink alcohol, you should do it in moderation.

While gin and tonic calories are lower with diet-tonic water's artificial sweeteners, the Mayo Clinic says that moderation is also key when using sugar substitutes.

These additives provide almost no calories and don't raise your blood sugar. While there don't seem to be any health hazards, the Mayo Clinic suggests limiting your intake because processed foods aren't as healthy as natural, whole foods. The same goes for diet soda, which contains artificial sweeteners.

If you're wondering how gin compares to other spirits when trying to find the lowest calorie alcohol, you might consider vodka and scotch. Both beverages have about the same number of calories, 97 per shot, as does a shot of gin. Furthermore, all three have only small doses of nutrients.

Gin is made from juniper berries, which give the spirit its flavor. Juniper berries have been studied for their antioxidant qualities. Antioxidants are substances that prevent or delay cell damage, among other functions, according to the U.S. National Library of Medicine.

A study in the March 2014 issue of Antioxidants has found that the essential oil of juniper berries studied in a lab setting in test tubes and on yeast cells protected the cells from aging due to its radical-scavenging activities. But this doesn't necessarily mean that it benefits human health.

A review of studies detailed in the November 2014 issue of International Scholarly Research Notices concluded that juniper berries have a long list of potential health benefits, including antioxidant qualities, pain relief properties, antibacterial action and more. However, scientists also noted more research needs to be done to determine their effects on humans.

Therefore, whether gin gets any benefit from its association with juniper berries is not clear. According to the list of nutrients in a shot of gin provided by the USDA, there are only trace amounts of beneficial nutrients.

Read more: 5 Hidden Health Benefits of Alcohol