Beer And Weight Gain: What's The Connection?

Beer is an alcoholic drink made from grain, such as barley, wheat or rye, that has been fermented with yeast. It is often associated with an increase in body fat, particularly around the belly, commonly referred to as a beer belly. But does beer really cause weight gain?

Beer is high in carbohydrates and alcohol but low in almost all other nutrients. The calorie content of beer depends on its strength — the more alcohol it contains, the more calories it contains. A 12-oz (355-ml) serving of regular beer, with approximately 4% alcohol content, has about 150 calories. Beer with a higher alcohol content will contain more calories.

Drinking beer can cause weight gain in a number of ways. Firstly, it increases your calorie intake. Beer contains as many calories as a soft drink gram for gram, so it has the potential to add a lot of calories to your diet. Secondly, beer may prevent fat burning. When you drink alcohol, your body prioritises breaking it down over other sources of fuel, including stored fat. Thirdly, beer contains phytoestrogens, plant compounds that can mimic the action of the female sex hormone oestrogen. It has been suggested that the hops in beer might cause hormonal changes in men that increase the risk of storing belly fat.

Research has found that light-to-moderate alcohol intake does not cause weight gain. Instead, regular heavy drinking may lead to weight gain over time. The National Institute on Alcohol Abuse and Alcoholism (NIAAA) defines heavy drinking as more than three drinks per day or seven drinks per week for females, and more than four drinks per day or 14 drinks per week for males.

The link between weight gain and drinking alcohol is stronger in men than in women, perhaps because men tend to drink more heavily. Men are also more likely to store fat around the belly when they gain weight.

Beer is high in calories

Beer also contains carbohydrates, with a 12-ounce serving of regular beer containing around 13 grams of carbs. This is similar to the number of carbs in a slice of bread.

The number of calories in beer varies depending on the type and strength of the beer. For example, a light beer has around 100 calories per 12-ounce serving, while a higher-alcohol or craft beer can contain between 170 and 350 calories per 12-ounce serving.

The high-calorie content of beer means that drinking it can lead to weight gain. This is especially true if you are drinking large quantities of beer or binge drinking regularly.

Beer affects your appetite

Drinking beer can have an impact on your appetite in several ways. Firstly, alcohol can lower inhibitions and impair judgement, making it harder to control portion sizes and leading to increased food consumption. This effect is well-known and often referred to as "the munchies". The more you drink, the more likely you are to eat more.

Secondly, alcohol may affect the hormones that regulate appetite, hunger, and satiety. It has been suggested that alcohol can inhibit the effects of leptin, a hormone that suppresses appetite, and glucagon-like peptide-1 (GLP-1), a hormone that inhibits food intake. By disrupting these hormonal signals, alcohol can increase feelings of hunger and decrease the sensation of feeling full.

Additionally, alcohol can stimulate nerve cells in the hypothalamus region of the brain, which is associated with appetite regulation. Animal studies have shown that alcohol can activate neurons in this area, triggering a sharp increase in appetite and leading to overeating. This effect may be independent of other factors and can cause intense feelings of hunger, even when adequate calories have been consumed.

Furthermore, alcohol can lower blood sugar levels, leading to cravings for sugary and carbohydrate-rich foods. This effect is particularly relevant for people with diabetes, who may experience low blood sugar levels when consuming alcohol, especially on an empty stomach.

While the impact of alcohol on appetite stimulation is still being studied, there is evidence to suggest that it plays a role in increasing appetite and energy intake. This, combined with the high calorie content of alcohol, can contribute to weight gain over time, especially when coupled with unhealthy food choices.

Beer can lead to poor food choices

Secondly, alcohol prevents your body from burning fat. When you consume alcohol, your body prioritizes breaking it down over burning fat. Regular drinking, therefore, can lead to an increase in body fat over time, especially in the abdominal region, commonly known as a "beer belly". This is supported by studies that have found a positive association between alcohol consumption and abdominal obesity, particularly in men.

Thirdly, alcohol can affect your hormones. It has been found to influence hormones that control appetite, hunger, and stress, such as cortisol, which is a stress hormone. Elevated levels of cortisol can increase abdominal weight gain and cravings for high-calorie foods. Alcohol can also affect the release of leptin, a hormone that controls satiety, and glucagon-like peptide-1 (GLP-1).

Finally, alcohol affects your judgment and lowers your inhibitions, making you more likely to make unhealthy food choices. Even the most dedicated dieter will struggle to resist the urge to indulge when intoxicated. This is supported by animal studies, which have shown that alcohol triggers hunger signals in the brain, leading to an increased urge to eat.

Beer affects your hormones

Secondly, alcohol can affect the hormones that control appetite, hunger and stress. For example, it can reduce your blood sugar level, which may increase hunger and lead to unhealthy food choices. This is supported by animal studies, which have found that alcohol activates cells in the brain that signal intense hunger.

Thirdly, beer contains phytoestrogen and prolactin, which can increase the body's estrogen levels and decrease testosterone levels. This can put you at risk of low testosterone.

Finally, alcohol can disrupt the communication between the nervous, endocrine and immune systems, causing hormonal disturbances that lead to serious consequences at physiological and behavioural levels. These include stress abnormalities, reproductive deficits, thyroid problems, immune dysfunction, cancers, bone disease and psychological and behavioural disorders.

Beer affects your sleep

The typical sleep cycle consists of three non-rapid eye movement (NREM) stages and ends with rapid eye movement (REM). During sleep, the body cycles through all of these stages every 90 to 120 minutes, with NREM sleep dominating the first part of the night and REM increasing during the second part. Each stage is necessary for sleep to feel refreshing, and for vital processes like learning and memory consolidation to occur.

When you go to bed with alcohol in your system, you experience more N3 sleep (deep sleep) and less REM sleep than usual, at least initially. Later in the night, once your body has metabolized the alcohol, you experience a rise in N1 sleep, the lightest stage of sleep. This can lead to frequent wakings and fragmented, low-quality sleep.

Alcohol also disrupts your sleep by interfering with circadian rhythms. Evidence suggests that consuming alcohol may decrease the body's sensitivity to cues like daylight and darkness, which trigger shifts in body temperature and the secretion of the sleep hormone melatonin. These fluctuations play a vital role in the sleep-wake cycle, and when they are weakened or absent, a person may feel alert when they want to sleep and sleepy when they want to be awake.

Consuming alcohol too close to bedtime is therefore likely to lead to a decrease in sleep quality, with fewer hours of sleep and more disruptions. Even low alcohol consumption hurts sleep quality, with a Finnish study finding that low amounts decreased sleep quality by over 9%. Experts recommend avoiding alcohol at least three hours before bed.

In addition, alcohol may cause or aggravate snoring and sleep apnea, a disorder that causes repeated pauses in breathing during sleep. Alcohol causes tongue and throat muscles to relax, and changes to blood vessels in the nose, leading to greater airway resistance in the nasal passages. These alterations significantly increase the likelihood and duration of breathing events during sleep.

Heavy alcohol use can also contribute to the development of insomnia, with as many as three-quarters of people with alcohol dependence experiencing insomnia symptoms when they drink. Insomnia is also very common in people who are in withdrawal or early recovery from alcohol addiction.

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