In the nutrition world, many foods and beverages supposedly increase metabolism — the reactions within the body that provide energy. In this Honest Nutrition feature, we investigate how our diet impacts our metabolism and whether certain foods and beverages really have a significant impact on metabolic rate.
Metabolism is the sum of the reactions in our cells that provide the necessary energy for functions such as movement, growth, and development.
Many factors can affect metabolism, including age, diet, biological sex, physical activity, and health conditions.
Basal metabolic rate is the energy required for the maintenance of critical body functions, such as breathing, while at rest. This is the largest contributor to the calories burned on a daily basis — also known as total energy expenditure.
The digestion and processing of food, including carbs, proteins, and fats, also require energy. This is known as the thermic effect of food (TEF). Some foods take more energy to break down than others, and this can slightly increase metabolism.
For example, fat takes less energy to digest than proteins and carbs. Proteins have the highest TEF out of the three macronutrients.
A person may think that specific foods and beverages can “rev up” the metabolism, but this is not necessarily true. Some foods take more energy to digest than others, and some foods may slightly increase the basal metabolic rate, but not much.
It is the total dietary intake that matters most.
For example, the TEF, the energy required to digest food, differs depending on the macronutrient content of the meal.
Here is the energy required to digest macronutrients:
- Protein: 10–30% of the energy content of the ingested protein
- Carbs: 5–10% of the ingested carbohydrates
- Fat: 0–3% of the ingested fat
The body uses the most energy to break down and store proteins, which is why it has the highest TEF.
TEF accounts for about 10% of total daily energy expenditure. For this reason, consuming a high protein diet may help us burn more calories overall.
Also, studies show that highly processed meals take less energy to digest than whole foods. This is likely due to the lower amounts of fiber and protein in highly refined foods.
Research has also shown that high protein diets can increase the resting metabolic rate (RMR), the calories burned while at rest.
A 2015 study found that in people with a high calorie diet, consuming a high amount of protein significantly increased 24-hour resting energy expenditure, compared with a low amount of protein.
A 2021 study determined that a high protein diet, consisting of 40% protein, produced higher total energy expenditure and increased fat burning, compared with a control diet that contained 15% protein.
Other studies have also shown that high protein diets increase daily energy expenditure, compared with low protein diets.
It is clear that higher protein diets may help people burn more calories on a daily basis, but what about specific foods?
Compounds in chili peppers, green tea, and coffee, for example, may slightly boost metabolism.
Studies show that consuming green tea catechin extract products may increase daily calorie expenditure by as much as 260 calories when paired with resistance exercise. It is important to note that most research in this area involves high doses of green tea extract supplements, and the results may not apply to people who simply drink green tea.
Some studies indicate that EGCG, a catechin found in green tea, has the potential to increase energy expenditure at 300 milligram (mg) doses. For reference, green tea contains about 71 mg of EGCG per 100 milliliter serving.
Meanwhile, the capsaicin in chili peppers can increase metabolic rate when taken in concentrated supplements. But the amount of this compound in a typical dish containing chili peppers is unlikely to significantly effect metabolism.
Along the same lines, one study showed that having a hot beverage containing ginger powder with meals may slightly increase TEF by about 43 calories per day. But this would have no significant effect on overall energy expenditure or weight loss.
To promote and maintain a healthy body weight, it is essential to focus on the overall quality and macronutrient content of the diet, rather than incorporating or eliminating specific foods.
As mentioned above, research shows that diets rich in protein and whole foods likely increase energy expenditure, compared with diets low in protein and high in ultra-processed foods.
While there is likely no harm in consuming moderate amounts of foods and beverages that are purported to improve metabolism — such as spicy foods, ginger, and green tea — this is unlikely to have a significant effect on energy expenditure or body weight.
A well-rounded diet with plenty of protein and fiber, from vegetables, fruits, nuts, seeds, and beans, for example, will support a healthy metabolism and promote overall health, as well.
Getting enough physical activity and maintaining healthy muscle mass can also help improve the overall energy expenditure.
Resistance training may be especially effective. A 2015 study showed that resistance training for 9 months could boost RMR by as much as 5% in healthy adults. And a 2020 review found that resistance exercise increased RMR, resulting in an average calorie increase of about 96 calories per day, compared with a control group.
Rather than focusing on specific foods, anyone hoping to boost their metabolism should consider their diet as a whole. A diet rich in protein and unprocessed foods may help increase energy expenditure, which could help maintain a healthy body weight.
Overall, having a healthy lifestyle that includes a nutritious diet and plenty of physical activity is the best way to support a healthy metabolism.