How many Calories Should I eat While taking Phentermine?

January 9, 2024 |

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This article will brief you on recommended calorie intake when taking phentermine and foods you should have or avoid to maximize the weight loss.

For effective weight loss with phentermine, you should take 1400-1600 calories daily. However, the exact calorie count differs for each person depending upon their age, BMI, gender, physical activity, and medical conditions.

Up next, I’ve discussed why this calorie deficit is enough to provide desired weight loss results, and you will find a guide on choosing the meals when dieting on phentermine.

So, if you’re interested in knowing all about foods that make weight loss difficult and their healthy substitutes, read on till the end.

How much should you eat while taking phentermine?

You should take about 1400-1600 calories daily to lose weight with phentermine.

However, the exact number of calories differs for each person as everyone requires different amounts of energy according to their age, height, exercise habits, sex, and health conditions.

The first step in determining how many calories you should use while dieting is calculating your body mass index (BMI).

Then find out how many calories you consume daily. For this purpose, you can use any BMI and calorie calculators available online.

After calculating your daily consumption, you’ll need to figure out the number of calories to cut down from your diet to create a calorie deficit matching your fitness goals.

But do not lower your calorie intake below the safety limit.

Health authorities have advised that women consume at least 1200 kcal and men take 1500 kcal each day.

Likewise, it would help if you bear in mind that trying to lose weight quicker than recommended can harm your health in ways you can’t even imagine.

According to health experts, losing 1 to 2 pounds in a week is the safe limit for weight loss, and if you limit your daily intake between 1400 to 1600 calories, you are highly likely to achieve your weight goals.

Following are a few tips you should follow for losing weight effectively and safely through diet therapy with phentermine:

  • Check with your doctor

You can only use phentermine when a physician prescribes it to you after analyzing your health. He would also provide you with guidelines about the diet plan.

Though you can set a calorie consumption goal by yourself, it is better that you take the help of your doctor. To get the best results, you should follow his recommendations for calorie intake.

Moreover, keep checking with him to reassess the intake goals according to changes in weight and exercise schedules.

  • Reassess your calorie allowance

Your energy requirements are not rigid and will change when you bring changes into your lifestyle.

When you lose weight, your BMI changes accordingly, and when you become more active, your calorie consumption increases.

Hence, you need to periodically reassess your calorie allowance to maintain an effective calorie deficit until you achieve your ideal weight.

  • Avoid skipping meals

When you are dieting to lose weight, you can easily get into the habit of skipping meals to reduce calorie intake.

This becomes even easier when you take an appetite suppressant like phentermine because you feel only a minimal urge to eat.

But this strategy is highly ineffective as food is the fuel to the human body, and you NEED this fuel to stay healthy and strong.

Instead of helping you achieve your health and fitness goals, skipping meals make weight loss even more difficult because metabolic rates become reduced in the body when the nutrient supply is short.

Hence, what you need to do for weight loss is; lower your calorie intake only a little bit and replace unhealthy food with nutritious substituents that boost metabolism to burn fats.

This begs the question:

Which foods are more beneficial when on a diet?

The next section is all about that and will help you heaps in choosing the right foods items for losing weight;

What to eat while taking phentermine to lose weight?

It is best to take foods that boost metabolism while taking phentermine so that maximum fat loss occurs when you are dieting.

delicious foods

Following is your to-do list to maximize fat burning with phentermine:

Take More Water

“Drink as much water as you can” is the foremost recommendation in any diet plan.

Because drinking a lot of water increases the success rate of weight loss programs.

When you increase your water intake while using phentermine, you will shred weight faster because phentermine would help you reduce fat deposition by limiting your food intake, and increased water consumption boosts fat metabolism in your body.

The efficacy of water in fat metabolism is associated with its thermogenic effects, as research shows that water-induced thermogenesis increases the rate of water loss by 30%.

Prioritize protein

Proteins are the food component that helps you lose fat mass and become smart without getting weaker or sick.

It is because protein metabolism takes more time, and its digestive products are incorporated into muscles instead of Adipose (fat) tissues.

Also, high-protein intake is necessary because your muscles naturally lose some of their protein components daily, and this process speeds up you reduce your carbs supply to the body.

Hence, if you do not consume enough protein content while dieting with phentermine, there is a chance you would lose weight due to muscular degradation instead of fat burning, which is more of a disadvantage.

Another reason protein will benefit you in getting fit and healthy is that it would increase lean muscle mass, make you stronger, and augment fat metabolism.

And you get the best results when you combine phentermine, protein, and physical activity.

According to research, fat oxidation due to exercise significantly increases with high- protein intake.

You can get natural protein from;

  • Eggs and poultry
  • Red Meat
  • Lentils and beans
  • Dairy products (milk, yogurt, cheese)
  • Nuts (peanut, almond, pistachio, walnut)
  • Seeds (pumpkin, flax, sesame, sunflower)

Increase fiber content

Dietary fibers are not broken down in the human digestive tract; instead, they pass undigested into feces. However, they will make you feel satisfied sooner, synergizing with the effect of phentermine.

Moreover, you feel full after consuming fewer calories when you take fibrous foods because fiber content would not affect the calorie count much.

Major sources of natural fibers are;

  • Vegetables (carrot, broccoli, beet, peas)
  • Fruits (Avocado, berries, apple, banana)
  • Whole grains (oats, wheat, corn, brown rice)
  • Seeds (chia, sunflower, pumpkin)
  • Take pH-boosting foods

The foods you eat affect your body’s pH balance; this is very important when analyzing the efficiency of a drug because each drug works best at a different pH level.

In this respect, phentermine goes hand in hand with Alkalizing foods because they increase urine pH, making it alkaline. And research has proven that it is slowly excreted through alkaline urine compared with acidic urine.

Hence, when you eat more alkaline foods, phentermine retention in the body is enhanced, providing lasting effects.

Foods to avoid on phentermine

When consumed with phentermine therapy, some foods enhance weight loss, but others do more harm than good.

To make your weight loss regime successful, you should identify such items and avoid them as much as possible.

Here, the rule of thumb is to avoid processed food because it contains all things you should avoid on a diet plan, including sugar, preservatives, empty calories, and acidic ingredients.

junk food fries and burger

Let’s find out why these things should be avoided on phentermine;

Empty calories

Bad or empty calories come from simple carbohydrates, which either provide instant energy to cells or become stored as fats but do not provide many nutritional benefits.

They are not used in the structural makeup of tissues, production of necessary vitamins, or building muscles.

Thus, consuming these calories is just luring yourself that you have provided necessary nutrition to your body when instead, you have just added more fat mass.

That is why some people report weight loss when on phentermine and then massive regain after quitting the drug.

Actually, it must have happened because they used empty calories and starved themselves, so the body consumed muscle protein to survive while their calorie intake was transformed into fat deposits.

Foods that contain empty calories are;

  • Cakes and sweets
  • Biscuits
  • Pasta
  • Sodas
  • Alcohol
  • Ice cream
  • Fast foods
  • Alcohol

Weight loss is difficult if you consume alcohol, and there are many reasons for it. The first one is that beer itself contains many empty calories.

Plus, it has acidifying effects on the body, which eventually reduces the anorectic drug’s efficacy.

Another reason is alcohol stimulates androgens which are known for their ability to reduce metabolic rates.

  • Acidic meals

When you take acidic meals resulting in a decrease in body pH, you reduce the efficacy of phentermine, causing it to be excreted sooner from the body.

As the research mentioned above inferred, acidic conditions increase the rate of phentermine excretion from 48% in alkaline urine to 84% in acidic urine.

Acidic foods include coffee, soda, and sweetened products.

  • Sugared food

Sugar is notorious for its fattening properties, and it is so for many good reasons. Most sweetened products are packed with simple carbohydrates that act as empty calories.

Hence, these products can make most of your daily calorie allowance but do not provide the required nutrition.

Such foods are also less filling. Hence you can be lured easily into overeating which eventually leads to fat buildup.

FAQs on Phentermine and calories intake

Does phentermine have calories?

No phentermine does not have any calories. Nutritional labels of phentermine-containing drugs show that it contains zero carbs, fats, and protein content.

Does phentermine make you burn more calories?

Yes, it improves calorie burning ability of the body but to a very small extent as it has mild thermogenic properties only.

How long should you wait to eat after taking phentermine?

You should wait 30 minutes to one hour before taking a meal after phentermine intake.

Does phentermine burn fat or just suppress appetite?

Majorly it suppresses appetite, giving a lasting sensation of fullness. However, it also shows mild fat-burning effects by increasing the thermogenesis in the body.

What to eat for breakfast while taking phentermine?

Foods like yogurt, fruits, oats, beans, and eggs are best to take for breakfast when using phentermine.

These food items provide you with a good amount of calories you would need to maintain your energy levels for most of your day and fuel metabolic processes.

To make this even more delicious, we have some tips for creating tasty and healthy breakfast recipes complementing phentermine.

  • Fruit Salads

Just slice and dice different fruits like avocados, barriers, kiwis, apple, and watermelon into a bowl, top it with black pepper or the spice of your choice and enjoy your easy, all-natural breakfast.

  • Fruit Smoothies

Blend your favorite fruits with low-fat yogurt and flavor your mornings with healthy, nutrient-packed smoothies.

  •  Eggs and omelets

Eggs are a perfectly healthy meal option, and there is a whole variety of egg recipes you can play with to match your own calorie needs; eat them poached, fried, baked, boiled, or scrambled!

A healthy option is to add some vegetables like capsicum, onion, or broccoli to a beaten egg and fry it with a teaspoon of butter.

  • Cereals

Yes, your breakfast friends since your childhood.

Cereals that are high in fiber and have lesser flavoring and sugars are a good breakfast option when dieting.

To make a nutritious, diet-meal; take a handful of cereal and top it with skimmed milk and fruits.


Appetite suppressants like phentermine make dieting much easier because they eliminate the urge to eat. However, lesser eating is also counterproductive for weight loss and also damages health.

Instead of blindly quitting meals, you should figure out your daily calorie consumption and set a fixed calorie allowance to create a calorie deficit.

Although this limit is different for everyone, it is mostly between 1400 to 1600 kcal daily.

To reach this daily calorie limit, you should consume healthy calories instead of bad or empty calories that lead to further fat deposits and a weaker body. For this matter, your physician can help you the most in designing a healthy diet plan.

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