In a recent video, natural pro bodybuilder and fitness educator Jeff Nippard dives into one of the most frequently asked questions in fitness: Can you really speed up your metabolism?
Known for his science-based approach to training and nutrition, Nippard has built a loyal following on YouTube by breaking down complex fitness topics using clear, evidence-backed explanations. With a background in biochemistry and years of competitive bodybuilding experience, he combines academic knowledge with real-world results.
In this video, Nippard tackles the metabolism mythos head-on—covering everything from water and green tea to cardio, muscle gain, reverse dieting, and even spicy food. He ranks each strategy based on how well it actually increases daily energy expenditure, organizing them into three categories: it works, it might work, and it probably doesn’t work.
“If we get to eat more calories while dieting, we may feel less depleted, perform better in the gym, and retain more muscle,” Nippard says. “So it’s worth figuring out.”
So, what does the science actually say? Here’s a full breakdown of his findings.
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What Is “Metabolism” in a Fitness Context?
When people say they want to speed up their metabolism, what they usually mean is increasing their metabolic rate—or how many calories they burn in a day.
This total energy expenditure (TEE) includes:
- Basal metabolic rate (BMR): Calories burned at rest
- Thermic effect of food (TEF): Energy used to digest and absorb food
- Exercise activity
- Non-exercise activity thermogenesis (NEAT): Movement like fidgeting or walking
“When we say someone has a fast metabolism, we mean their body burns a lot of calories,” Nippard explains. “A slow metabolism means they burn fewer calories and have to diet on less food to see weight loss.”
What surprises many is how wildly individual metabolism can be—even between people of the same size and sex. A 2022 study published in Science examined over 6,000 people and found that at the same weight of 176 pounds, one person might burn just 1,400 calories per day, while another burns over 5,700.
That’s more than a 4,000-calorie difference at the same weight. So what actually determines metabolic rate—and can you change it?
Proven Ways to Increase Metabolism
Some methods consistently show a measurable increase in daily energy burn. These aren’t gimmicks—they’re backed by science.
1. Build More Muscle
Muscle is more metabolically active than fat. One pound of muscle burns approximately 6 calories per day at rest, while a pound of fat only burns about 2 calories per day.
That may not sound like much, but the numbers add up.
“If you put on 30 pounds of muscle over the next five years, you’d burn about 180 more calories per day just sitting still,” says Nippard.
That’s roughly the equivalent of four kiwis a day—for free. Of all metabolism-boosting strategies, building muscle offers the biggest long-term payoff.
2. Do Cardio (But Don’t Overdo It)
Cardiovascular exercise clearly increases calorie expenditure—but there’s a twist. The body compensates by lowering spontaneous movement (NEAT).
“Let’s say you go for a jog that burns 500 calories,” Nippard explains. “You might fidget and move around less later in the day, so you only burn 350 calories through NEAT instead of your usual 500.”
This energy compensation effect reduces the net gain, but not entirely. On average, you retain about 72% of the calories burned from cardio.
So while cardio isn’t as efficient as it seems, it still helps boost metabolism, especially when paired with strength training and a well-managed diet.
3. Increase NEAT (Non-Exercise Activity Thermogenesis)
NEAT refers to all the movements you do outside the gym—standing, walking, fidgeting, cleaning.
You can increase NEAT by:
- Parking further away
- Taking the stairs
- Standing while working
- Doing light chores between meetings
“I call these little activities ‘NEAT smuggling’,” says Nippard. “It works—sneaking in more movement during the day can have a meaningful impact on your daily calorie burn.”
NEAT can vary by up to 2,000 calories per day between individuals. For many, increasing daily movement is one of the easiest ways to support fat loss and metabolic health.
What Might Help (But Needs More Evidence)
Some methods show a small effect in the lab or in limited studies—but they’re unlikely to transform your metabolism on their own.
1. Drinking Cold Water
Drinking water burns calories—especially cold water, which your body must heat to body temperature.
Each glass of cold water burns about 8 extra calories.
“Cold water gives a bigger boost than room temperature,” Nippard explains. “But I’m still putting water in the ‘might work’ category.”
Why? Because the total impact is small, and other factors (like reduced movement) may cancel out the extra burn. That said, water can help with fullness and appetite control, making it a helpful tool for fat loss.
2. Eating Spicy Foods (Capsaicin)
Capsaicin, the compound that gives chili peppers their heat, has a mild thermogenic effect. A 2017 meta-analysis found that it increased daily energy expenditure by about 69 calories—but only in people with a BMI over 25.
“In a spicy meal, you might get a 20-calorie metabolic boost at best,” says Nippard. “It pales in comparison to the 700 calories in the meal itself.”
Still, spicy food can slow eating speed and increase water intake, which may promote better portion control.
3. Wearing a Weighted Vest
There’s growing interest in tricking the body into burning more calories by adding weight.
A case study on natural bodybuilder Eric Salazar showed promising results: he wore a 34-pound weighted vest for 90% of the day during a fat loss phase and experienced fewer negative side effects while getting to 5% body fat.
“The theory is that the body senses the extra weight and increases metabolism accordingly,” Nippard explains. “It probably works—but we need more data.”
Some researchers believe a system in the body called the gravitostat senses added load and adjusts hunger and energy expenditure. For now, weighted vests stay in the “might work” category—but they’re promising.
4. Reverse Dieting
Reverse dieting involves slowly increasing calories after a fat loss phase to rebuild metabolism.
While popular in the fitness world, evidence is mixed.
“I’ve seen people increase calories and maintain weight,” Nippard notes. “But I don’t think it’s necessary to go super slow after a diet.”
He recommends jumping back to new maintenance calories right after dieting, then increasing gradually from there.
What Probably Doesn’t Work (Despite the Hype)
Some methods are consistently shown to have little to no meaningful impact on metabolic rate.
1. Green Tea
Green tea is often marketed as a metabolism booster—but the science is underwhelming.
A 2021 review found that 3 of 4 studies showed no effect on energy expenditure. One study did show a 79-calorie boost, but it included only 10 subjects over 24 hours.
“There are at least two long-term studies showing no benefit for fat loss,” Nippard says. “So I’m putting green tea in the ‘probably doesn’t work’ category.”
2. Saunas
While saunas increase heart rate and oxygen use slightly, the calorie burn is minimal.
Ten minutes in a sauna might burn 19 calories, versus 14 calories sitting in a regular room. That’s a 5-calorie difference—roughly one stick of gum.
3. Cold Exposure and Ice Baths
Shivering burns calories—but not many.
A 10-minute ice bath burns about 28 calories, just 14 more than sitting at room temp. Despite its popularity on social media, cold plunges offer negligible metabolic benefits.
“The numbers are pretty underwhelming,” Nippard admits.
4. Frequent Meals
Many believe that eating more often “stokes” the metabolic fire. But studies don’t support this.
A 2012 respiration chamber study found no difference in energy expenditure between eating 3 meals per day or 14 meals—as long as the total calories were the same.
A 2015 meta-analysis of 15 studies also found no significant fat loss benefit from more frequent meals.
“Meal frequency should be based on preference and appetite control—not metabolism,” Nippard says.
Other Effective Strategies to Protect Metabolism
Even with the best methods, metabolism can adapt. But two underrated strategies help mitigate this:
1. Avoid Very Low-Calorie Diets
The more aggressively you cut calories, the more your metabolic rate slows. Instead, aim to lose 0.5–1% of your body weight per week to preserve muscle and energy levels.
2. Use Adaptive Tools Like MacroFactor
Tracking tools can help keep your metabolism in check during fat loss. Nippard recommends MacroFactor, an app he co-created that adjusts your intake based on real-time changes in your weight and metabolic response.
“It updates your diet based on your unique metabolism—just like a coach would,” he says.
Unlike standard calculators or wearable devices, which can be off by hundreds of calories, MacroFactor uses dynamic tracking to personalize calorie targets as your body adapts.
Bottom Line: Yes, You Can Boost Your Metabolism—But Only Some Strategies Work
Forget the gimmicks. If your goal is to increase your daily calorie burn, the best ways to do it are:
- Build more muscle
- Stay active throughout the day
- Do moderate cardio
- Avoid extreme dieting
Other methods—like spicy foods, cold water, or green tea—might help slightly, but they won’t transform your results on their own.
“Even if you have a slow metabolism, you can still lose weight,” says Nippard. “What really matters is being consistent with training, nutrition, and lifestyle habits.”
By focusing on the proven strategies and ditching the hype, you can build a stronger metabolism—and a stronger body—for the long haul.
