What To Eat While Taking Phentermine (breakfast & launch)

January 8, 2024 |

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Phentermine is an FDA-approved drug for weight loss and obesity, designed for those with a BMI (body mass index) higher than 30 or higher than 27 (if you have other health conditions). It works through appetite suppression.

Considering that it’s a prescription drug that has a potential for abuse, you surely want to maximize its benefits before you reach the limit. After all, it’s only recommended for use within 12 weeks to avoid increased risks.

These are the foods you should eat while taking phentermine:

  • Be sure to consume enough protein to help you continue building muscles instead of fat. High-protein foods also take more work to metabolize, digest, and use by your body. That means you burn more calories in processing them.
  • Healthy high-fiber foods make you feel full, so they boost the effects of phentermine.
  • Fruits and vegetables also add volume to what you eat but with fewer calories.
  • And don’t forget to drink 8 glasses of water every day.

What other foods should you eat to get the best results while taking phentermine and which ones should you avoid?

Is it better to take phentermine with food or skip meals altogether?

Keep reading to find the answers below.

Is it Better to Take Phentermine with Food?

To achieve the full effect of phentermine, it’s usually taken about an hour or a few hours before eating. Your doctor might recommend taking the second one about an hour or two after breakfast, but that’s usually done in preparation for lunch.

But would phentermine work better if you skip eating food altogether?

That could work for some people, especially those doing certain diet techniques such as intermittent fasting. However, if you also plan to do an intense workout session to lose weight more quickly, we don’t recommend skipping any meals.

Instead, it’s better to take phentermine with food. You can pick the foods that would work best when you’re taking phentermine or opt for meal replacement shakes.

Also, fasting or going below 1,200 calories a day can activate your body’s survival instincts and trick your systems into believing that there’s food scarcity. If that happens, holding on to your fat stores is one of your body’s defense mechanisms to survive.

Instead of burning fats, your body slows down your metabolism.

You don’t want that to happen. So, make sure you keep your metabolism at a normal or higher rate so that you can continue burning fats and losing weight.

Best Foods to Eat While Taking Phentermine

1. Water

No matter what diet plan you’re following, it’s always important to drink at least 8 glasses of water each day.

However, the rule is even more important if you’re taking phentermine. By drinking water, you can help improve your body’s functions and help you stay hydrated throughout the day.

Did you know that there are times you might feel hungry but your body actually needs just water on those occasions? You can maximize phentermine’s appetite suppression effect by keeping yourself full with water and hydrated.

In that way, your body won’t misinterpret thirst for hunger.

It might be a good idea to use chilled water because it tastes better and can feel more refreshing to your body. If you prefer something warm, that’s also good. You can even drink a cup of green tea – and that can count towards your daily water quota.

2. Protein-rich Foods

Phentermine is best taken with foods that are rich in proteins.

Remember that in dieting, you want to lose fats, not proteins. So, taking in more proteins makes sense because the amino acids in these foods can help provide ample material for protein-building in your body.

By taking more proteins, you help your body have more toned, stronger muscles – and you can even burn calories even if you aren’t active.

How does that happen?

High-protein foods actually take more work in your body to digest, metabolize, and use. More work means more calories burned in processing them! That can surely work to your advantage if you’re trying to lose weight.

Another good reason to get more protein is that proteins are “heavy” foods that make you feel full sooner and keep that feeling for a longer amount of time. However, be sure to trim out the fats from the protein-rich meats you’re eating.

Good sources of protein to eat while taking phentermine:

  • Lean beef or pork
  • Skinless chicken or turkey
  • Tofu
  • Fish
  • Low-fat dairy
  • Eggs
  • Nuts and seeds (cashews, hazelnuts, flax seeds, walnuts, chia seeds, and almonds)
  • Legumes and beans (soybeans, kidney beans, black beans, chickpeas, and peanuts)

3. Fiber

Many people might say that fiber is the magic weapon for weight loss. That’s because fiber-rich foods can essentially make you feel full, yet have a lot fewer calories than meat and other foods.

It can be easier to resist eating more food if you already feel full.

This means that fiber can easily boost phentermine’s appetite suppression effects. By eating fiber-rich foods, you can satisfy your hunger with fewer calories.

Some good sources of fiber you can eat while taking phentermine:

  • Whole grains (brown rice, quinoa, bulgur, oatmeal, and barley)
  • Beans
  • Nuts
  • Berries
  • Bran cereal
  • Baked potatoes (with skin)
  • Fruits and vegetables

4. Alkalizing Foods

Foods that maintain an alkaline urinary pH (7.5 to 8.0) help keep phentermine in your body for a longer time because the substance will be eliminated at a slower rate.

Studies show that phentermine is excreted faster in an acidic urinary pH ranging from 5.5 to 6.0. As much as 84% of the phentermine dose was excreted unchanged by the kidneys within just 24 hours.

In contrast, only around 48% was excreted over the same period by study subjects with an alkaline urinary pH ranging from 7.5-8.0.

Why is that important?

To maximize the effects of a medication or drug, such as phentermine, you have to keep it in your body for a longer time. By getting excreted at a much slower rate with an alkaline urinary pH, you can enjoy its effects for a longer time.

Some popular alkalizing foods you can take with phentermine:

  • Almonds
  • Chestnuts
  • Tofu
  • Tomatoes
  • Onions
  • Carrots
  • Stevia
  • Cinnamon
  • Cucumbers
  • Apples
  • Grapes
  • Curry
  • Ginger
  • Lemons
  • Berries
  • Bananas
  • Mustard
  • Chili pepper
  • All herbs

What to Eat For Breakfast While Taking Phentermine

Plan your meals when taking phentermine. You can use the list above as a guide on what you should eat and avoid.

Here are some meal ideas for breakfast while taking this weight-loss pill:

  • Tuna salad with hummus, honey mustard, and lots of lettuce
  • Chicken strips with spinach and goat’s cheese
  • Tomato, spinach, and goat’s cheese omelet
  • Oatmeal with banana and Greek yogurt
  • Blueberry and oats bowl
  • Tomato and watermelon salad
  • Boiled or poached eggs

Can You Eat Fruit While Taking Phentermine?

Yes, absolutely! Fruits and vegetables contain a lot of water and fiber – and both are a perfect complement to your phentermine intake, as discussed above.

Aside from making you feel full more quickly with fewer calories, fruits and vegetables are also packed with vitamins and minerals that can boost your metabolism and make you healthy.

For best results, choose whole fruits instead of fruit juices because they contain more fiber.

If you plan on eating more vegetables, remember to cook them in a healthy way. Avoid fried, stir-fried, or sautéed veggies because they contain unnecessary oil. Go for roasted or steamed veggies instead.

And if you’re making a salad, opt for healthy dressings instead of calorie-packed mayonnaise and similar options.

How Many Calories Should I Eat While Taking Phentermine?

This varies for everyone, especially depending on these factors:

  • Current weight
  • Gender
  • Amount of physical activity

In general, you don’t want to go below 1,200 calories per day for women or 1,500 calories a day for men. Doing so can activate your body’s survival mode and make you store more fats instead of burning them.

If you’re active and regularly do intense workouts, you might need more calories.

The recommended calorie intake for women is 2,000 calories a day and 2,500 calories for men.

So, if you’re on phentermine, you can consider getting calories between 1,200 and 2,000 for women, and between 1,500 and 2,500 for men.

What Foods Should you Avoid When Taking Phentermine?

There are certain (healthy and unhealthy) foods to avoid when taking this diet medication:

1. Sugar

Have you noticed how there are so many unhealthy foods that are also too sweet? That goes for many junk foods like soda, donuts, and processed fruit juices.

Although they don’t negatively interact with phentermine to cause dangerous side effects, sugary foods can undermine your weight-loss efforts.

Excess sugars in the body get stored as fats. The more fats your body stores, the more weight you might gain.

You’re taking phentermine to lose weight, right? Always remember that. So, you should avoid foods that directly interact with the substance or increase your chances of gaining weight.

What’s worse, sugar can also increase your risks for diabetes and elevated insulin resistance, which can lead to obesity if left unchecked.

Sugary foods to avoid when taking phentermine can include the following:

  • Candies
  • Processed meals
  • Frozen meals
  • Store-bought fruit juices
  • Dried fruits

While there are also plenty of fruits that are high in sugar, the sugar levels in processed foods are higher and they’re unhealthy, too.

2. Simple Or Refined Carbohydrates

Aside from sugars, there are also lots of simple carbohydrates that can increase your fat stores and increase your blood sugar content to unhealthy levels.

Here are some of the foods with simple carbohydrates that you should best avoid while taking phentermine:

  • Table sugar
  • Products with white flour (such as white bread)
  • Candies
  • Chocolate
  • Cakes of any form
  • Jam
  • Cookies, biscuits, and crackers
  • Soda
  • Packaged cereals
  • Pasta
  • Flour tortillas

3. Alcohol

In a previous article, we discussed why it is dangerous to combine alcohol and phentermine.

Aside from containing a high amount of sugar and so-called “empty calories” that actually make you gain weight, alcohol can also affect your liver.

The combination of phentermine and alcohol can inhibit your liver’s fat-burning systems for several days. When that happens, you have a reduced chance of burning fats. So, you can either lose muscle mass or simply keep your fat stores in the status quo.

4. Junk Foods & Processed Meats

Junk foods and processed meats contain a lot of salt, unhealthy oils, and empty calories that could make you gain weight.

And while you shouldn’t feel guilty about treating yourself to some on occasion, make it a habit to choose healthier foods instead of the following:

  • Fast food meals
  • Salted potato chips
  • Processed meats (sausages, salami, canned meat, bacon, corned beef, etc.)

5. Foods With Trans-Fats

It’s also important to avoid foods with trans-fats, whether you’re taking phentermine or on a regular diet.

Trans-fat is bad because it can increase your risk of heart disease. Note that phentermine can also cause heart problems, so mixing these two together can greatly increase your likelihood of developing heart disease or experiencing a heart attack.

Foods with trans fats include:

  • Margarine
  • Vegetable oil

6. Acidifying Foods

Remember the alkalizing foods that can help keep phentermine longer in your body as discussed above?

You’d want to avoid the foods that trigger the opposite effect: acidifying foods. These acidifying foods can make you gain weight and inhibit your body’s fat-burning processes.

Plus, they make you excrete phentermine at a much faster rate. The shorter phentermine stays in your system, the lower its effects.

Here are some acidifying drinks and foods you should avoid while taking phentermine:

  • Soda
  • Coffee
  • Alcohol
  • Ice cream
  • Sugars
  • Butter
  • Products that contain white flour, including bread and pastries

Phentermine can only be taken for a few weeks, a maximum of 12, to avoid serious negative side effects such as dependence or drug addiction. So, you should ensure that every single day counts towards your weight-loss goals. It’s best to stick to the best foods to eat and avoid while you’re taking the obesity drug.

But if you really want sustainable weight loss that lets you maintain the new weight, you can also try healthier alternatives that you can take without limits. Why not try PhenQ?

PhenQ: A Better Alternative Weight-Loss Drug To Phentermine?

Like phentermine, PhenQ helps you lose weight through appetite suppression.

You get to curb those cravings, but without fear that you can become dependent on it.

As a dietary supplement, PhenQ doesn’t require a prescription and isn’t a scheduled drug that you have to closely monitor. There are no known side effects in using PhenQ even with long-term use.

Plus, you don’t have to fear experiencing the serious withdrawal effects similar to phentermine.

Instead, you can quit anytime you think you’ve achieved your goals – and take PhenQ again if you feel the need for it, anytime you want to.

Aside from crushing cravings, PhenQ also works by burning fats and reducing fat accumulation – and that’s something that phentermine doesn’t do.

It simply suppresses your appetite and gives you an energy boost.

Another advantage of using PhenQ over phentermine is that it can boost your metabolism and helps balance your mood. While phentermine can cause depression and other mood disorders, PhenQ helps keep you motivated and positive.

More importantly, it has the right blend of caffeine and other natural ingredients that boost and sustain your energy, keeping you ready to work out at all times.


Why am I Still Hungry While Taking Phentermine?

Phentermine isn’t a wonder drug that stops hunger 100% so you won’t eat the entire day. It actually works by suppressing your appetite, but you’ll still feel hungry to some degree.

Sometimes, there are those who take phentermine and still feel hungry, but reduced cravings for foods that are more likely to make you gain weight, including carbs. This can help you make healthier choices.

Plus, your body continues to work like it is supposed to, even if you’re taking phentermine.

That means that you still need fuel (food!) to provide energy for various processes. So, your body will also continue to recognize your need for sustenance.

Ideally, phentermine will help suppress your appetite. But if you notice that you continually feel hungry and still have your cravings, the drug might not work for you.

Talk to your doctor. Phentermine might not be the right drug for you.

Also, you might be experiencing tolerance. It happens when the drug no longer works because its mechanism of action has been recognized by your body and gets ignored.

However, don’t quit phentermine without asking your doctor! It can cause serious withdrawal symptoms.

Severe withdrawal symptoms can include:

  • Nerve damage
  • Tremors
  • Congestive heart failure
  • Seizures
  • Stroke
  • Cardiac arrest, which can be deadly!

What Is The Best Time of Day to Take Phentermine?

To achieve the best effects (appetite suppression and energy boost) with phentermine, it’s best to take it at least 30 minutes to an hour before breakfast.

Your doctor might also add a second dose a few hours after breakfast or an hour before lunch.

Don’t take the last phentermine dose at night or close to your bedtime because it can lead to insomnia.

Can I Take my Vitamins With Phentermine?

Be extra cautious about taking any vitamins or medications with phentermine because it has plenty of drug interactions that can cause serious side effects. It can even cause spotting or bleeding with oral contraceptives!

Tell your doctor about the vitamins you’re taking if they prescribe you phentermine. They will know the best course of action and whether you need to stop taking your vitamins or find another alternative to the prescription drug.

How Soon After Taking Phentermine Can I Eat?

It varies depending on a lot of factors, including your age, gender, the drug dose, and what you eat while taking phentermine. However, for many people, phentermine’s effects can begin in about 30 minutes to an hour, while others might take a few more hours.

Talk to your doctor if you think the drug doesn’t immediately work for you. You might need a change in dosage or your doctor might prescribe a different weight-loss drug.

Can I Drink Coffee While Taking Phentermine?

No. Both coffee and phentermine are stimulants that affect your brain’s chemical balance. Coffee could increase phentermine’s side effects, which can be dangerous because the prescription drug can affect your heart.

Do I Have to Eat While Taking Phentermine?

Yes. Don’t skip meals while taking phentermine because your body might go into survival mode and hold on to your stored fats instead of burning them. You might experience a plateau and think the drug isn’t working the way it should.

How Much Water Should I Drink With Phentermine?

Be sure to drink at least 8 glasses of water per day when you’re taking phentermine or any other weight-loss drug for that matter.

Water makes you feel fuller, and your body won’t confuse thirst with hunger.

Plus, it might sound counterintuitive, but your body can actually lose more water weight if you drink enough water.

That’s because dehydration or having an insufficient water supply also activates your body’s survival instincts and it will hold on to your water supply by storing them. Those stored water can increase your weight.


If you’re taking phentermine, it’s important to follow a healthy diet and make sure you’re getting the nutrients your body needs. Here are some tips for what to eat while on phentermine.

Avoid processed foods, sugary drinks and snacks, and fatty foods.

Instead, focus on eating whole fruits and vegetables, lean protein, and whole grains. And remember to drink plenty of water.

Thirst can often be mistaken for hunger. By following a healthy diet while taking phentermine, you can help ensure that you lose weight safely and effectively.

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