Negative Calories – Black Coffee

When it comes to losing weight, the benefit of coffee and caffeinated drinks on the body is controversial.  Studies into the effect of caffeine on weight loss are not definitive and often based on animal models.  While caffeine has been found to stimulate the metabolism and decrease appetite, the way we consume it may in fact have negative impacts on our weight.  In addition to this, although generally considered a safe substance, if abused caffeine can have very dangerous effects on the body.  Many people can’t contemplate beginning their day without a cup of coffee or two, so is this helping your weight loss, or is your caffeine habit holding you back?

Caffeine is found in a number of forms, the most well known of course is coffee, but it can also be found in energy drinks, chocolate, cocoa, tea , cola soft drinks and a number of weight loss drugs.

coffee in snow

Benefits of caffeine for weight loss

Helps the body to burn more calories

Studies have found that caffeine increases thermogenesis, and therefore stimulates the body to burn energy.  This results in more effective burning of calories, which may in turn lead to weight loss.

Appetite Suppressant

It has also been suggested that caffeine works as a short term appetite suppressant, meaning that it may result in less hunger and subsequently less food consumption.

More energy

Caffeine also gives us more energy, which is the main reason why most people can’t start their day without it.  This may give you that kick start that is needed to get out of the house and hit the gym or the treadmill for a workout.  More exercise is definitely beneficial for weight loss, so in this indirect way caffeine may also be beneficial.

Diuretic Function

The final way that caffeine may increase weight loss is through its diuretic function.  In many people caffeine will result in a loss of water, which in turn reduces weight, although it should be noted that this type of weight loss is solely due to fluids and not due to loss of fat.  This function may be useful for those prone to water retention.

The potential for weight gain

Whilst there are clearly some benefits of caffeine to weight loss, there are also many situations where caffeine containing beverages are more likely to result in weight gain. (See thoughts about dieting here)

Non-black coffee is likely to add more calories to your diet

When people drink coffee, it is rarely a standard cup of black coffee with no additions.  Coffee in this simple form does not contribute many calories and so will not have an effect on weight.  Commercial ‘designer’ coffees however, are another story.  Some of these coffees are so large and so packed full of syrups, sugar and fat in the form of full fat milk or cream that they can top out at around 800 calories.  This is likely to be more than you should be consuming for a whole meal if you are trying to lose weight!  On top of this, aside from calcium and protein, they contribute very little nutritional value and thus are mainly empty calories.

Amount of sugar in energy drinks and cola soft drinks

Energy drinks and cola soft drinks can be similarly problematic.  Along with the caffeine, they also contain a huge amount of sugar; therefore any benefit that is received for weight loss from the caffeine is completely undone by the amount of calories you are consuming in the drinks. Chocolate and cocoa based products are also unlikely to help weight loss, as not only is the amount of caffeine lower, but they are generally high in fat and sugar as well.  The best way to receive benefits from caffeine containing drinks is to stick to black coffee, with a little non fat milk and artificial sweetener if you need it, and choose sugar free energy and soft drinks.

Energy boost is limited

While caffeine may give you the energy boost you need to get through the day, it doesn’t last long- an average of two to four and half hours in the body.  After this it is common to feel a slump in energy, which can lead to decreased physical activity and be detrimental to your efforts to lose weight.

black coffee

Dangers of caffeine for weight loss


Caffeine, whilst generally considered safe, is addictive.  Drinking beverages such as coffee and energy drinks may mask the symptoms of tiredness, but they do not replace the need for the body to sleep.  Thus by constantly loading yourself with caffeine rather than getting the rest required, you can end up exhausted and susceptible to illness.  Many people find themselves needing more and more caffeine in order to function, leading to excessive intake and possibly dangerous results.

Too much caffeine can cause side effects

Whilst caffeine in moderation is usually safe, high levels of intake can have unpleasant and even dangerous results.  Recommended intake is less than 500mg-600mg per day.  An 8oz cup of coffee contains around 95-200mg, with instant coffee containing slightly less.  Energy drinks can contain between 80 to 300mg per serve depending on the brand.  Too much caffeine can cause side effects such as nervousness, anxiety, insomnia, irritability, restlessness and headaches.  In severe cases, consumption of large amounts of caffeine, usually from an excessive number of energy drinks, can have serious effects such as cardiac arrhythmias and arrest.  It is not recommended to consume high levels of caffeine before sport, as this can place added stress on the heart.

Danger of dehydration

Dehydration, due to the diuretic effect of caffeine is also common, and those who consume large quantities should ensure that they are also drinking plenty of water to replace lost fluids, particularly during sport or in hot climates.

The verdict

In moderation and in the right form, caffeine may have a small beneficial effect on weight loss, although some of this is likely to be water based.  However, it should not be used in large quantities as a weight loss tool.  A high intake of caffeine containing beverages that are also high in fat or sugar should be avoided, as this is likely to undo any benefits due to the high calorie content, and in fact is more likely to cause weight gain. For more ideas on healthy foods visit Eating Healthy Today.


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