The Best Time to Drink Water to Support Your Metabolism, According to Dietitians

Before you reach for your coffee, try a glass of water first.

Reviewed by Dietitian Jane Leverich, M.S., RDN

Key Points

• Adequate hydration helps support metabolic processes that keep your body functioning.
• Dietitians recommend drinking water first thing in the morning to support metabolism.
• Prioritizing hydration, exercise and sleep are all strategies to support your metabolism.

If you’ve ever searched for ways to “boost” your metabolism, you’ve probably come across everything from trendy supplements to elaborate morning routines. But one of the most impactful habits may also be one of the simplest: staying hydrated.

Water plays an important role in many of the body’s essential functions, including nutrient transport, temperature regulation, circulation, digestion and the countless biochemical reactions involved in metabolism.

While drinking water won’t dramatically increase your metabolic rate, adequate hydration helps support the processes that keep your body functioning at its very best. In fact, even mild dehydration may affect energy levels, cognitive performance, physical performance and overall well-being. That’s why many dietitians consider hydration a foundational part of a healthy lifestyle.

And while staying hydrated throughout the day matters most, experts say there may be one time that offers particular benefits–that time being first thing in the morning. After several hours without fluids overnight, you may wake up slightly dehydrated, making that first glass of water an easy way to replenish fluids and support the body’s normal metabolic function. Here’s why dietitians say hydrating first thing in the morning may be the best time to drink water to support metabolic health.

Why First Thing in the Morning Is the Best Time

It Helps Replace Fluids Lost Overnight

Even while you’re sleeping, your body continues to lose fluids through normal processes like breathing and perspiration. As a result, many people wake up slightly dehydrated. According to Jenna Zaika, RD“Starting the day with water can help restore hydration status.”

Hydration supports everything from circulating nutrients and regulating body temperature to removing waste and supporting the chemical reactions involved in energy production. While drinking a glass of water won’t dramatically increase your metabolism and metabolic rate, it can help ensure your body has the hydration it needs to function optimally and support these essential processes throughout the day.

It Supports Essential Metabolic Processes

Metabolism refers to the countless chemical reactions that occur throughout the body to sustain life. These reactions include everything from converting food into energy to supporting normal cellular function.

Water plays a role in many of these processes. “Water is required for many biochemical reactions involved in metabolism,” says Danielle Smiley, RDN, LDN, CD-N. “Adequate hydration supports circulation, nutrient delivery, waste removal and cellular function.”

Zaika agrees, noting that nutrient transport, energy production, temperature regulation and waste removal all depend on adequate hydration.

It May Help Support Physical Activity

Hydration plays an important role in physical activity. “When people feel adequately hydrated, they are often better able to engage in movement and exercise,” says Smiley.

Research suggests that even mild dehydration may negatively affect physical performance by reducing endurance, strength and overall exercise capacity. Dehydration may also contribute to feelings of fatigue and make physical activity feel more challenging.

Because regular movement contributes to daily energy expenditure, maintaining adequate hydration may indirectly support metabolic health by helping make physical activity feel more manageable. In other words, hydration doesn’t directly boost metabolism–but it can help support the behaviors that do.

It May Support Cognitive Function and Energy Levels

Hydration doesn’t just affect physical performance–it supports brain function, too. According to Zaika, even mild dehydration can affect concentration, mood and overall cognitive performance.

Starting the day hydrated may help you feel more energized, focused and ready to tackle your daily tasks. This is because rehydrating in the morning helps to restore fluid balance, which supports circulation and the delivery of oxygen and nutrients throughout the body.

Feeling your best may also make it easier to engage in everyday habits that support overall health, whether that means staying active, preparing nourishing meals or maintaining a consistent routine.

Does Drinking Water Actually Boost Your Metabolism?

According to Smiley, “There is some truth to the claim, but it is often overstated.”

Research suggests that drinking water may temporarily increase energy expenditure through a process known as water-induced thermogenesis. However, the effect appears to be relatively modest and is unlikely to result in significant weight loss or meaningful increases in metabolic rate on its own.

“Rather than thinking of water as something that ‘boosts’ metabolism, I encourage people to think of it as creating the conditions that allow the body’s metabolism to work as intended,” Zaika explains. Smiley agrees: “Hydration is foundational to metabolism, not a metabolism hack.”

In other words, drinking water will not dramatically speed up your metabolism, but chronic dehydration may make it harder for your body to function at its best.

Other Strategies to Support Your Metabolism

Hydration is important, but it’s only one piece of the metabolic health puzzle. Dietitians also recommend focusing on the following habits:

• Prioritize protein throughout the day. “For many adults, aiming for protein at meals and snacks throughout the day can help support overall health, satiety and muscle preservation,” says Zaika.,
• Incorporate resistance training. Muscle tissue is metabolically active, meaning it requires energy even when at rest. Smiley notes that lean muscle mass is one of the strongest predictors of resting energy expenditure, making strength training an important component of metabolic health.
• Get adequate sleep. “Poor sleep can negatively affect appetite-regulating hormones, recovery and metabolic health,” says Smiley.
• Avoid chronic under-fueling. Highly restrictive diets and long-term undereating can negatively affect energy levels, nutrient intake and muscle preservation. “A well-nourished body functions more effectively than one that’s constantly being deprived,” says Zaika.
• Manage stress and prioritize self-care. “Do things that bring you joy,” says Zaika. Chronic stress can influence sleep, eating habits, physical activity and overall well-being, making self-care an often-overlooked component of metabolic health.

Our Expert Take

If you’re looking for the best time to drink water to support your metabolism, dietitians agree that first thing in the morning is a great place to start. After several hours without fluids, rehydrating your body upon waking can help to restore fluid balance and support essential functions involved in metabolic health. That said, there isn’t a magic time of day that will suddenly rev up your metabolism. Instead, adequate hydration works as a foundation for overall health and helps support the many processes your body relies on to function at its best.