What Should I Eat While Taking Phentermine?

by Rakib Sarwar, RPh
Published on January 23, 2019 and last updated for accuracy on September 19, 2022

When you begin your weight loss plan, knowing the right things to eat while on phentermine can be somehow difficult. There are several diet plans to avoid when taking phentermine and the right foods to eat. When taking Phentermine, you will experience a suppressed appetite, but most importantly, you may need to eat the right foods and feed well (1, 2).

What is Phentermine?

Phentermine is a popular amphetamine-like drug used for its appetite-suppressing benefits. It facilitates weight loss by reducing your hunger and giving you that feeling of fullness faster and for longer (3).

Just like most other popular weight loss medications, phentermine is meant to be part of your overall weight loss regimen. It is most appropriate for individuals who are either obese or have not been able to lose as much weight as they would love to with a combination of exercise and diet. It is not for you if all you want is to lose some few pounds (4).

Phentermine is classified among the Schedule IV drugs. This classification is for those drugs whose potential for being overdosed or abused are quite high. Although the real potential for phentermine appears to be quite low, it still does not change the fact that people can easily abuse it (5).

General Rules For Your Weight Loss Diet Plan When Taking Phentermine

Here are a few diet rules you may wish to pay attention to when taking phentermine:

Choosing the right eating plan is important

With so much contrasting weight loss diet views on the internet, choosing the diet that will work well for you when taking phentermine can be a bit hard. Some of these diets come with very contradictory views. While some praise the huge benefits of adding complex carbohydrates to your diet plan, others will warn that you avoid anything carbohydrate outrightly when taking phentermine. These contradicting opinions make it hard for you to choose, however, you should know what you think will work well for you (2).

There are people who believe carbs will make it hard for them to lose weight. If you think this is true, then you should choose a diet plan that does not include carbs. Instead of continuing with carbs, replace them with other choices like protein, fiber, and vegetables. If you are in doubt of which options will help you lose weight, you can experiment first. Do different diets on different weeks and check the results. However, there are some universal truths you may wish to adhere to when on a diet plan. Such truths will ensure you get the best from your diet plans for weight loss (2).

Appetite Suppressant + Eating Plan
This 2-minute quiz unlocks an easy intermittent fasting fat loss program with appetite suppressant, customized for you so you can manage your health and form habits that last.
Appetite Suppressant + Eating Plan
This 2-minute quiz unlocks a intermittent fasting fat loss program with appetite suppressant, customized for you so you can manage your health and form habits that last.

You must eat to lose weight

Eating adequately is one important thing you may wish to do to lose weight. When you fail to give your body enough food, it will convert whatever comes in to fat. Generally, experts say you should consume about 1200 calories per day. However, some factors determine what you eat such as weight, height, age, and sex. Your phentermine doctor will give the best advice on how many calories you should take daily. The right daily calorie intake will maximize your weight loss results (2).

What to Eat While On Phentermine

There are right foods and wrong foods to eat while taking phentermine. Let’s see some of the foods that go well with phentermine and maximize your weight loss efforts.


Drinking as much water as possible is the foremost rule of any diet plan. This same rule applies to what you eat while on a phentermine meal plan. When taking phentermine, you should take about 8 glasses of water each day. Taking adequate amount of water will go a long way to improve your body functions, assist your body to release more of its water weights, beat dehydration and help you learn not to mistake thirst for hunger pangs. To ensure you drink adequate water daily, take chilled water or green tea. The body absorbs chilled water more easily in addition to the fact that it has a better taste (2).


When on a phentermine meal plan, consuming enough protein is something you may wish to do. This is because the digestion, metabolism, and absorption of proteins take longer. These proteins also linger in your stomach for longer, and this helps you feel full faster and stay full for longer. If you are combining exercises and phentermine, it is important you take enough protein. Taking enough protein, in this case, will ensure you lose weight and not lean muscles (2).

The protein you consume build up the lean muscle in your body, and this lean muscle ensures you stay stronger and toned. The lean muscles facilitate the adequate burning of calories even when you do not exercise regularly. With the right amount of protein, you will enjoy faster body metabolism and more efficient fat-burning. Some very good protein sources to help you get adequate protein supply when taking phentermine include turkey, skinless chicken, fish, tofu, lean beef, eggs, low-fat dairy, and nuts (2).


Fiber may not be one of the magic weight-loss weapons, however, eating foods high in healthy fiber content will make you feel full faster, and this will help you resist the urge to eat more than your body requires. Although taking phentermine alone is enough to suppress your hunger pangs, adding some high-fiber foods will help you feel full with fewer fats and calories. Some natural sources of fiber include brown rice, nuts, whole grains, beans, and baked potatoes with the skin, vegetables, berries and bran cereal (2).

Vegetables and Fruits

Fruits and vegetables should constitute an important part of your phentermine meal plan. This will enable you to consume the same quantity of food with much fewer calories. Most of the fruits and vegetables can help you feel full and add very few fats and calories to your body. Choosing whole fruits over the commercial fruit juices will ensure you get more fiber content. Also, ensure you cook your vegetables well and serve them with the appropriate dressings (2).

Alkalizing Foods

Eating alkalizing foods while on phentermine will ensure you maintain an alkaline urinary of 7.5-8.0. This helps you maximize the phentermine in that your body will eliminate the phentermine at a much slower rate. Almost every fruit and vegetable have this alkalizing property, and this means they will keep your body’s alkaline levels low, and this will help you enjoy the benefits of phentermine more. Some of these benefits include suppressed appetites and lower energy levels throughout the day. Other common alkalizing foods include tofu, chestnuts, stevia, almonds, chili pepper, mustard, cinnamon, ginger, curry, and all types of herbs (2).

Foods to Avoid When Taking Phentermine

There are a number of foods that cannot go hand-in-hand with your phentermine meal plan. Here are some of the foods you should avoid while taking phentermine:

Simple Carbohydrates

Some foods are very rich in carbohydrates and should not be taken with phentermine. Some common foods that are high in carbohydrates include table sugar, candy, white flour products, cake, chocolate, soda, cookies, and processed cereals. Your body is able to digest these carbohydrates, and this can bring about serious changes in your sugar levels.

Additionally, your body stores these carbs as fat instead of utilizing them as fuel. If carbs must be included in your diet, make sure they are complex carbs which are known to take longer before they digest. These complex carbs come with many good fiber, minerals, and some vitamins. Some good examples of good complex carb sources include whole grain bread, legumes, oatmeal, brown rice, and whole wheat pasta (2).


The added sugar in your diet supplies fructose to your body, and only your liver can process this fructose. If your liver is busy processing other foods, it will store the extra sugar you take as fat. This extra sugar when stored much will increase your risk of obesity as it increases your insulin resistance, increases your risk of diabetes and spikes up your cholesterol levels. Sugar can easily be found in most of the food items mentioned earlier and can hide in almost all processed foods, such as frozen meals. Also, commercial fruit juices and dried fruits come with extra sugar. Freshly squeezed juice and freshly harvested fruits are the best (2, 6).


Just like with the higher sugar levels, your liver’s functions can be affected by your alcohol intake to the point that the fat burning system of your body can be weakened for days, making your liver unable to burn any fats (2, 7).

Acidifying Foods

All the foods mentioned above are also known to be acidifying in addition to their fat-burning inhibiting nature. This makes these food options some of the foods you may wish to try to avoid when taking phentermine. This is because when you take these acidifying foods while on phentermine, the phentermine gets excreted faster from your system and its effectiveness will be greatly jeopardized. So, make sure you avoid alcohol, soda, sugars, coffee, ice cream and any products made from white flour (2).

Final Words

While on phentermine, ensure you eat the right types of foods. Remember it doesn’t end with losing weight. You have to maintain the new weight after the whole weight loss exercise for the whole effort to be worth it. It is the changes you make while on phentermine that will determine how long your good results lasts (2).


(1) https://www.webmd.com/drugs/2/drug-4151/phentermine-oral/details

(2) https://www.phentermine.com/blog/what-to-eat-while-taking-phentermine/

(3) https://www.mayoclinic.org/healthy-lifestyle/weight-loss/expert-answers/phentermine/faq-20057940

(4) https://www.drugs.com/phentermine.html

(5) https://www.opss.org/faqs/what-phentermine-and-will-it-cause-positive-result-urine-drug-test

(6) https://www.cardiosmart.org/Healthwise/d008/06/d00806

Read Next
Phentermine is known as an effective, FDA-approved weight loss supplement.…