A “fifth” is the common term for a standard 750 milliliter (mL) bottle of distilled spirits, such as whiskey, vodka, or gin. This volume originated from the historical measurement of one-fifth of a U.S. gallon. Assessing the health implications of consuming this volume requires translating the total liquid into a precise measure of pure alcohol for comparison against public health recommendations.
Quantifying the Consumption
To accurately assess the alcohol content, one must understand the definition of a standard drink. In the United States, one standard drink contains approximately 14 grams of pure alcohol. This amount is typically found in a 12-ounce regular beer, a 5-ounce glass of wine, or a 1.5-ounce shot of distilled spirits at 40% Alcohol by Volume (ABV, or 80 proof).
A 750 mL bottle of 40% ABV spirits holds roughly 25.36 fluid ounces of liquid. When divided into 1.5-ounce servings, a single “fifth” bottle contains nearly 17 standard drinks. Consuming an entire fifth of spirits over the course of a week means ingesting the equivalent of 17 standard drinks.
Comparing Consumption to Health Guidelines
Consuming 17 standard drinks per week places an individual above the levels considered low-risk by national health organizations. The U.S. Dietary Guidelines and the National Institute on Alcohol Abuse and Alcoholism (NIAAA) suggest that adults limit daily intake to two drinks or less for men and one drink or less for women.
When considering weekly totals, the low-risk threshold is defined as no more than 14 drinks per week for men and no more than 7 drinks per week for women. The pattern of drinking one fifth per week (17 standard drinks) exceeds the weekly limit for men and more than doubles the limit for women. Drinking above these limits is classified as “heavy drinking” or “at-risk drinking,” which significantly increases the likelihood of developing alcohol-related health conditions.
Health Implications of Heavy Weekly Intake
Consistently drinking 17 standard drinks per week poses numerous risks to nearly every major organ system. The liver is particularly susceptible because it is the primary organ responsible for metabolizing alcohol. This level of intake can lead to alcoholic fatty liver disease (steatosis), where fat accumulates in the liver cells. Over time, this damage can progress to more severe conditions like alcoholic hepatitis and cirrhosis, which is the irreversible scarring of the liver.
The cardiovascular system is also placed under strain by heavy alcohol use. Regular excessive consumption can cause an increase in heart rate and lead to spikes in blood pressure. It is associated with an elevated risk of developing arrhythmias (irregular heartbeats) and cardiomyopathy (weakening of the heart muscle).
Alcohol interferes with the brain’s communication pathways, manifesting as impaired coordination and difficulty with clear thinking and memory. Prolonged heavy drinking can lead to significant cognitive deficits, potentially contributing to alcohol-related dementia. Alcohol is also a central nervous system depressant, and high-level use often exacerbates or triggers mental health issues.
This pattern of heavy intake can intensify feelings of anxiety and depression. While alcohol may temporarily mask these symptoms, its long-term effect on brain chemistry ultimately worsens mood disorders. The body’s immune system also becomes compromised, making the individual more vulnerable to various illnesses.
Recognizing Problematic Use and Dependency
A pattern of drinking a fifth a week can signify a move toward an Alcohol Use Disorder (AUD). AUD is characterized by an impaired ability to stop or control alcohol use despite adverse social, occupational, or health consequences. Key behavioral indicators include developing tolerance, where increasing amounts of alcohol are needed to achieve the desired effect, and a loss of control, such as drinking more than intended.
Other signs include neglecting responsibilities at work, school, or home, or continuing to drink despite negative health or relationship problems. If the body has adapted to alcohol, attempting to cut back can result in withdrawal symptoms like anxiety, tremors, or insomnia. Self-assessment tools, such as the AUDIT questionnaire, can help individuals evaluate their consumption. Seeking guidance from a healthcare professional or accessing support resources is recommended for those concerned about their level of consumption.