ProLon Diet Review: All You Need To Know (2024)

The ProLon Fasting Mimicking Diet is a five-day plant-based restricted-calorie meal program designed to imitate metabolic changes that can occur from fasting for a short time. It’s intended to “reset your metabolism by helping your body improve its response to insulin, which is essential for optimal health and plays a role in weight loss,” explains Melina Jampolis, M.D., a board-certified physician nutrition specialist and Forbes Health Advisory Board member.

Rather than cutting out calories completely, you simply consume a smaller amount during the diet. On the first day, you’ll eat about 1,100 calories, while days two through five have between 700 and 800 calories per day.

The entirety of what you’ll eat during this time is sent to you in five boxes—one for each day of the diet—which contain various energy bars, soups, drinks, supplements and snacks. Users follow the diet’s regime for one week out of the month before returning to their normal diet, but the best benefits are seen after three consecutive months, the company notes.

The ProLon Diet works through what it calls “fasting mimicking,” according to Dr. Jampolis. “It’s high in fat and lower in protein and carbohydrates and, per the creator, is supposed to trick the body into thinking that it is fasting even though you are eating food throughout the day, albeit small amounts — 34% [to] 54% of your normal calorie intake,” she explains.

Specifically, ProLon claims that the following occurs during the five-day cycle:

• Day 1: Your body moves into a fasting and fat-burning state, preparing for “cellular clean-up,” where nutrient sensing pathways are reportedly cleared
• Day 2: Fat-burning in the body ramps up, initiating ketogenesis, or ketone production, which help turn glucose into energy
• Day 3: Fat-burning and ketone production continue, increase
• Day 4: Cellular cleaning and renewal, and fat-burning continue
• Day 5: Fast is completed, and cellular cleaning temporarily continues

The ProLon Diet isn’t a one-and-done fast, either, especially if your intention is to lose weight. “For weight loss, it is meant to be done once a month for at least three months to ‘reset’ your metabolism, and to maintain the health benefits, you must follow the diet every 1-6 months,” Dr. Jampolis says.

For shorter fasting designed to support intermittent fasting, the brand also offers a one-day fast called the ReSet by ProLon. Still, if it’s weight loss, fat loss, improved metabolic health or a kickstart to a healthier lifestyle you’re after, ProLon recommends its five-day fast.

On the ProLon Diet, you’re limited in what you can eat. The company sends you a box containing all that you can consume during the fast. It’s whole food, vegetarian and free of gluten and lactose.

Foods You Can Eat

The five-day fast includes one box for each day with:

• Plant-based energy bars
• Soups (flavors may include vegetable, minestrone, vegetable quinoa, tomato and mushroom)
• A variety of snacks, drinks and supplements

The amount of food you get varies per day, with the most on Monday and least later in the week. But the contents are meant to be good for you. The drink that’s included contains glycerol, which Dr. Jampolis says is “supposed to support you when your body has depleted its carbohydrate stores (glycogen).”

The ReSet by Prolon option includes:

• Breakfast: One Fast Bar, herbal tea, and algal oil packet
• Lunch: One tomato soup, almond and kale crackers serving, and two NR-1 packets
• Afternoon: One olives packet and herbal tea
• Dinner: One butternut squash soup and the program’s energy I.F. Bar

Foods to Skip

You’ll avoid most foods during the ProLon Diet, ideally sticking only to what is provided in the boxes you receive. The company states “​​additions are discouraged to minimize the risk of breaking the fast.”

However, ProLon does allow you to make a select few additions to what is included:

• Unlimited herbal teas (unsweetened and caffeine-free)
• All types of sparkling water (though no sweeteners of any kind are permitted)
• Caffeine (up to 140 milligrams per day)
• Dried herbs or spices added to soups or other foods in the diet (up to one tablespoon per day)
• Sea salt (up to one tablespoon per day)
• Lemon, squeezed, not eaten (up to two slices per day)
• Sugar-free gum (up to two slices per day)

ProLon specifies you should add food to the diet “only as a last resort if you are so incredibly hungry that you feel like you are going to break the fast.” In these cases, suggested additions include “a slice or two of apple, one stalk of celery or one small Persian (“baby”) cucumber of 5 to 6 inches in length per day.”

Potential upsides of the ProLon Diet, according to Dr. Jampolis, include:

• Possible reduction in belly fat: This is likely one of the most important possible benefits of the diet, as a reduction in belly fat “leads to weight loss, reduction in blood sugar and cholesterol [and] reduction in inflammation,” notes Dr. Jampolis.
• Potential to improve aging: The diet was actually created with the intent of improving aging rather than for losing weight, says Dr. Jampolis, and it has the potential to do that. The possible reduction in belly fat “may help support healthy aging by inducing a process called autophagy in which older cells are replaced by new, healthier cells,” she explains.
• Realization of gluten or lactose sensitivities: By cutting out most foods for five days, you may have the opportunity to more easily discern a food sensitivity. If digestive issues like bloating, diarrhea or abdominal pain occur during the ProLon diet, Dr. Jampolis suggests talking to your health care provider and potentially trying a larger elimination diet.

There are also downsides of the ProLon Diet to consider, including:

• High cost: The ProLon Diet is expensive. While discounts may be offered, particularly for those doing their first fast with ProLon or buying multiple boxes, the five-day fast box runs $249. The ReSet by ProLon box costs $44.99, though, and again, discounts may be available.
• Limited body changes likely due to the short-term nature of the diet: Due to the fact that the ProLon Diet induces short-term ketosis, which helps preserve muscle, Dr. Jampolis says that “body composition changes are likely limited to mainly belly fat.” She also says “there is no evidence that this method is superior to other methods of fasting or even long term caloric restriction.”
• Low calorie intake may not be suitable for all: The ProLon Diet is very low in calories, which may not make it appropriate for everyone. A daily calorie intake should remain above 1,200 per day for women and 1,500 per day for men to avoid potential health risks, according to the Harvard Medical School. Dr. Jampolis notes that someone who is active “may have trouble exercising while following the diet and certainly hunger could be an issue, especially the first few days.” As well, she suggests people with diabetes consult their health care provider before trying and recommends against pregnant or breastfeeding people doing the ProLon Diet. People who miss important nutrients, minerals and micronutrients provided by a well-balanced diet may experience poor health effects, the World Health Organization notes, such as weight loss, fatigue and vitamin deficiencies. These and other symptoms stemming from the lack of nutrients and minerals, according to some dietitians, could trigger disordered eating or an unhealthy relationship with food.

Those who may benefit the most from the ProLon Diet are people with pre-diabetes or people with diabetes who have excess belly fat, or those who are generally healthy and looking to kickstart a health plan.

“Anyone who is overweight could benefit, but this approach is best suited in my opinion to those with insulin resistance, where the body does not respond adequately to insulin,” she says. This can “lead to excess belly fat, high blood sugar, high cholesterol and is associated with inflammation.”

The ProLon Diet may not be right for:

• People who are pregnant or nursing
• Those with eating disorders
• Those who are underweight
• Those who are very active
• Older people who are frail
• Those with allergies to any of the components of the kit

Dr. Jampolis also points out that people with some knowledge of nutrition may be able to recreate this diet on their own without the cost. However, a do-it-yourself version may not include all of the benefits that the ProLon Diet may be able to offer.