Can You Lose Weight with Diet Alone?

When looking to lose weight, several factors may influence your progress. While diet and exercise…

When looking to lose weight, several factors may influence your progress.

While diet and exercise are often combined to promote weight loss, some may wonder whether you can lose weight via dietary modifications alone.

This article explains whether losing weight is possible by solely manipulating your diet and includes recommendations to help you get started.

When it comes to weight loss, a few key factors determine your level of success.

Calories in vs. calories out

The factor that plays the biggest role in weight loss is maintaining a consistent calorie deficit.

This is defined as eating fewer calories than you burn on a daily basis.

Over time, this will lead to weight loss because your body will be burning through its fat and carbohydrate stores for energy (1, 2).

While you’re in a calorie deficit, your body turns to its fat cells and glycogen, the body’s stored form of carbs, to make up for the lack of energy from food intake.

Dietary factors

You can employ numerous dietary strategies to lose weight.

The goal is to eat slightly fewer calories than your body needs for weight maintenance, promoting a gradual weight loss.

The number of calories you need to eat to lose weight is highly variable and depends on a lot of factors, including your sex, height, weight, and other genetic factors.

Some common weight loss strategies include (3, 4):

  • Low carb diets. Limiting your carb intake to 50–150 grams daily may help decrease your intake of commonly overconsumed high carb foods. Low carb diets often prioritize protein and fiber-rich vegetables, which help manage hunger and promote appetite control.
  • Ketogenic diets. Very low carb intakes of fewer than 50 grams daily can stimulate ketogenesis. This process, in which fat is used as the primary energy source, may help regulate your hunger levels.
  • High protein diets. Protein intakes of 0.5–0.7 grams per pound (1.2–1.6 grams per kg) per day promote building and maintaining lean body mass, which supports your metabolism and may reduce overeating by helping you feel full for longer.
  • Intermittent fasting. Restricting eating to a designated time period may reduce your overall calorie intake and improve diet adherence.

While these strategies may promote weight loss, most experts recommend reducing your calorie intake gradually and including nutrient-rich, whole foods that are high in fiber and protein.

This method supports your overall health and reduces some of the negative side effects of dieting while promoting noticeable weight loss.

Exercise factors

Exercise is another important tool often utilized to help promote weight loss.

Physical activity enhances the “calories out” side of the equation, further promoting a calorie deficit and fat loss.

When looking to lose weight, cardio exercises like running, swimming, and cycling are often preferred over resistance exercises, as they tend to burn more calories minute for minute.

That said, for a well-balanced training program, doing both cardio and resistance training provides the best results.

This is in part due to how regular resistance exercise can increase your muscle mass, which may help boost fat loss, as muscle burns more calories than fat (5, 6).

Fortunately, many of today’s exercise programs include a combination of cardio and resistance training, checking off both boxes at once.

Summary

The most important factor for weight loss is maintaining a calorie deficit, which can be accomplished through either your diet, exercise habits, or both.

Though diet and exercise are most often combined to help promote weight loss, some people choose to focus on their diet alone.

Doing so comes with several potential benefits.

Allows you to devote full attention to diet

Oftentimes the task of losing weight can seem overwhelming, especially for people with a significant amount of weight to lose.

Though physical activity is important for reasons other than weight loss, eliminating it from the weight loss equation allows you to devote your full attention to your nutrition.

With one less variable to focus on, you may be able to better adhere to your diet, potentially improving your long-term weight loss success (8).

However, while most people don’t have trouble losing weight by diet alone initially, they may struggle with maintaining their weight loss in the long term without adding physical activity to the equation (7).

More time-efficient for those with a busy schedule

For those with a hectic daily schedule, fitting in both meal planning and exercise during the day can be a daunting task.

A 2013 study found that young adults perceive time restriction as one of the main barriers to improving their diets (9).

By focusing on dieting alone, you can free up valuable time in your schedule, allowing for a more sustainable approach to weight loss.

Once you establish a solid dietary routine, you can gradually add exercise to boost your weight loss progress.

Summary

While dietary and exercise modifications are often combined to achieve weight loss, only focusing on your diet may help devote your full attention to your nutrition. It may also feel more manageable than including exercise in the equation.

Although you may see some weight loss progress by only focusing on your diet, there are some downsides to consider.

Risk of weight regain

One of the major potential downsides of focusing on your diet alone is experiencing weight regain after some time.

In fact, a recent study in adults with overweight examined the effects of various exercise interventions on weight loss (10).

They broke participants into four groups: a calorie-restriction-only group, a strength training group, an endurance training group, and a strength-endurance group.

Each group followed a diet that provided a 25–30% calorie deficit for 6 months, during which only the exercise groups performed physical activity 3 times per week.

The study found that all groups initially lost a similar amount of weight, though most gained a significant amount of the weight back after 3 years.

The exception was the strength-endurance group. Those in this group kept the weight off after 3 years, suggesting that exercise plays a big role in maintaining weight loss.

By foregoing exercise, you may be increasing your chance of experiencing weight regain after some time.

You miss out on the positive metabolic effects of exercise

Participating in regular exercise can help burn calories, boost weight loss, and offer other important metabolic benefits.

Metabolic benefits refer to how your body converts the foods you eat into energy. Having more lean muscle and less body fat helps your body burn more calories while at rest, which is advantageous when you’re looking to lose weight (11).

The main metabolic effects of exercise include (12, 13):

  • improvements in muscle and bone mass
  • improvements in insulin sensitivity, a key marker of carbohydrate metabolism
  • increased resting metabolic rate, or how many calories you burn at rest
  • the prevention of metabolic syndrome, which is a cluster of conditions that increase your risk of heart disease, stroke, diabetes, and artery disease

Still, the specific metabolic effects depend on the type of exercise performed.

For example, a 2015 review of 66 studies looked at various treatment methods for adults with overweight, including different types of exercise (14).

They found that resistance exercise was especially important for promoting fat loss and supporting lean muscle mass.

Also, participating in regular resistance exercises has been shown to promote healthy bone and muscle mass (15, 16, 17).

This is especially important as you age, as both muscle mass and bone density start to slowly decline after the age of 30 (18).

It’s also important to include some endurance exercise, such as walking, running, cycling, or swimming, as doing so has been shown to boost heart health and decrease the risk of many diseases (19).

By passing on exercise, you may miss out on some of its positive metabolic effects.

In the end, the best approach to weight loss is the one you can stick to. Aim to find a form of exercise you enjoy and can stick to consistently, just like you would with your diet.

Summary

Though achieving weight loss by focusing on diet alone comes with a few potential benefits, it’s important to keep in mind some of the benefits you may miss out on by excluding exercise from your routine.

Though combining dietary and exercise modifications is most efficient for weight loss, you can surely accomplish healthful weight loss by concentrating on your diet alone.

How much weight do you want to lose?

An important deciding factor is how much weight you’re looking to lose.

For those with significant weight to lose, it’s probably best to include both diet and exercise for the best results (14).

Meanwhile, those who are only looking to lose 10–15 pounds (4.5–6.8 kg) will likely be able to accomplish this through dieting alone.

To get started, determine your calorie maintenance calories, then subtract about 500 calories to get your starting daily calorie goal. This should help you lose 1–2 pounds (0.5–1 kg) per week (20).

A common science-backed dieting approach focuses on eating a nutrient-rich, high fiber, high protein diet to help boost weight loss progress (21).

That said, you may want to utilize one of the aforementioned dieting strategies that you like the best, as finding an eating pattern you can stick to consistently is key.

Keeping your protein intake fairly high should help you maintain muscle mass and keep you full. Aiming to eat around 0.5–1 gram per pound (1.2–2.5 grams per kg) may help you achieve this.

Some people like to increase their protein intake even further, up to 1.0–1.4 grams per pound (2.3–3.1 grams per kg) of body weight (22, 23).

The rest of the calories will come from carbs and fats, depending on your preference.

While counting calories is not necessary to lose weight, some find it helpful to ensure progress, and studies have linked it to weight loss (24, 25).

Several smartphone apps can make counting calories much easier.

For more specific diet guidance, it’s best to consult a registered dietitian.

Set realistic goals

The more calories you cut from your diet, the faster you’re likely to lose weight.

Nevertheless, reducing your calorie intake too low comes with negative side effects, such as loss of muscle mass, increased appetite, nutrient deficiencies, poor energy, and a decrease in daily calories burned (26, 27, 28).

Therefore, it’s best to set realistic weight loss goals of no more than around 1 pound (0.5 kg) per week to prevent these side effects.

Lastly, when it comes to dieting, consistency is key. Thus, you’ll want to follow an approach you can stick to in the long term.

Summary

Healthy weight loss can be accomplished through dietary modifications alone, such as gradually reducing your calorie intake and setting attainable goals that can be adhered to long term.

While there are advantages to losing weight through a combination of diet and exercise, some chose to focus on diet alone to promote weight loss.

When looking to lose weight, the most important factor is maintaining a small but consistent calorie deficit, which you can do by manipulating your diet, exercising, or both.

Healthy weight loss can be achieved by making dietary changes alone, though your progress may be slower than if you also included exercise. Also, you may miss out on some of the metabolic and health benefits of physical activity.

Before committing to a weight loss diet, it’s best to consult a healthcare professional, especially if you take medications or have any underlying health conditions.